Revert "Remove PSTL from the top-level monorepo (#143717)"revert-143717-aballman-remove-pstl

This reverts commit f8ed45611b75ecac1d459aa6ae3b7051d435abe6.

117 files changed, 22172 insertions, 4 deletions

diff --git a/llvm/CMakeLists.txt b/llvm/CMakeLists.txt
index 4f542bb..902f977 100644
--- a/llvm/CMakeLists.txt
+++ b/llvm/CMakeLists.txt
@@ -109,7 +109,7 @@ endif()
 # This allows an easy way of setting up a build directory for llvm and another
 # one for llvm+clang+... using the same sources.
 # These projects will be included when "all" is included in LLVM_ENABLE_PROJECTS.
-set(LLVM_ALL_PROJECTS "bolt;clang;clang-tools-extra;compiler-rt;cross-project-tests;libclc;lld;lldb;mlir;openmp;polly")
+set(LLVM_ALL_PROJECTS "bolt;clang;clang-tools-extra;compiler-rt;cross-project-tests;libclc;lld;lldb;mlir;openmp;polly;pstl")
 if (${CMAKE_SYSTEM_NAME} MATCHES "AIX")
   # Disallow 'openmp' as a LLVM PROJECT on AIX as the supported way is to use
   # LLVM_ENABLE_RUNTIMES.
@@ -141,7 +141,7 @@ endforeach()
 # As we migrate runtimes to using the bootstrapping build, the set of default runtimes
 # should grow as we remove those runtimes from LLVM_ENABLE_PROJECTS above.
 set(LLVM_DEFAULT_RUNTIMES "libcxx;libcxxabi;libunwind")
-set(LLVM_SUPPORTED_RUNTIMES "libc;libunwind;libcxxabi;libcxx;compiler-rt;openmp;llvm-libgcc;offload;flang-rt;libclc")
+set(LLVM_SUPPORTED_RUNTIMES "libc;libunwind;libcxxabi;pstl;libcxx;compiler-rt;openmp;llvm-libgcc;offload;flang-rt;libclc")
 set(LLVM_ENABLE_RUNTIMES "" CACHE STRING
   "Semicolon-separated list of runtimes to build, or \"all\" (${LLVM_DEFAULT_RUNTIMES}). Supported runtimes are ${LLVM_SUPPORTED_RUNTIMES}.")
 if(LLVM_ENABLE_RUNTIMES STREQUAL "all")
diff --git a/llvm/docs/CMake.rst b/llvm/docs/CMake.rst
index fc82235..72f19fd 100644
--- a/llvm/docs/CMake.rst
+++ b/llvm/docs/CMake.rst
@@ -588,7 +588,7 @@ enabled sub-projects. Nearly all of these variable names begin with
 
   The full list is:
 
-  ``bolt;clang;clang-tools-extra;compiler-rt;cross-project-tests;libc;libclc;lld;lldb;mlir;openmp;polly``
+  ``bolt;clang;clang-tools-extra;compiler-rt;cross-project-tests;libc;libclc;lld;lldb;mlir;openmp;polly;pstl``
 
   .. note::
     Some projects listed here can also go in ``LLVM_ENABLE_RUNTIMES``. They
@@ -610,7 +610,7 @@ enabled sub-projects. Nearly all of these variable names begin with
 
   The full list is:
 
-  ``libc;libunwind;libcxxabi;libcxx;compiler-rt;openmp;llvm-libgcc;offload``
+  ``libc;libunwind;libcxxabi;pstl;libcxx;compiler-rt;openmp;llvm-libgcc;offload``
 
   To enable all of them, use:
 
diff --git a/pstl/.clang-format b/pstl/.clang-format
new file mode 100644
index 0000000..8a110c1
--- /dev/null
+++ b/pstl/.clang-format
@@ -0,0 +1,20 @@
+BasedOnStyle: LLVM
+
+Language: Cpp
+Standard: Cpp11
+
+IndentWidth: 4
+ColumnLimit: 120
+
+AlwaysBreakTemplateDeclarations: true
+AlwaysBreakAfterReturnType: All
+PointerAlignment: Left
+AllowShortIfStatementsOnASingleLine: false
+BreakBeforeBraces: Allman
+
+# Disable formatting options which may break tests.
+SortIncludes: false
+ReflowComments: false
+
+# Indent preprocessor directives
+IndentPPDirectives: AfterHash
diff --git a/pstl/CMakeLists.txt b/pstl/CMakeLists.txt
new file mode 100644
index 0000000..592e11d
--- /dev/null
+++ b/pstl/CMakeLists.txt
@@ -0,0 +1,103 @@
+#===-- CMakeLists.txt ----------------------------------------------------===##
+#
+# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+#
+#===----------------------------------------------------------------------===##
+cmake_minimum_required(VERSION 3.20.0)
+set(LLVM_SUBPROJECT_TITLE "Parallel STL")
+
+set(PARALLELSTL_VERSION_FILE "${CMAKE_CURRENT_SOURCE_DIR}/include/pstl/internal/pstl_config.h")
+file(STRINGS "${PARALLELSTL_VERSION_FILE}" PARALLELSTL_VERSION_SOURCE REGEX "#define _PSTL_VERSION .*$")
+string(REGEX REPLACE "#define _PSTL_VERSION (.*)$" "\\1" PARALLELSTL_VERSION_SOURCE "${PARALLELSTL_VERSION_SOURCE}")
+math(EXPR VERSION_MAJOR "(${PARALLELSTL_VERSION_SOURCE} / 1000)")
+math(EXPR VERSION_MINOR "((${PARALLELSTL_VERSION_SOURCE} % 1000) / 10)")
+math(EXPR VERSION_PATCH "(${PARALLELSTL_VERSION_SOURCE} % 10)")
+
+project(ParallelSTL VERSION ${VERSION_MAJOR}.${VERSION_MINOR}.${VERSION_PATCH} LANGUAGES CXX)
+
+# Must go below project(..)
+include(GNUInstallDirs)
+
+set(PSTL_PARALLEL_BACKEND "serial" CACHE STRING "Threading backend to use. Valid choices are 'serial', 'omp', and 'tbb'. The default is 'serial'.")
+set(PSTL_HIDE_FROM_ABI_PER_TU OFF CACHE BOOL "Whether to constrain ABI-unstable symbols to each translation unit (basically, mark them with C's static keyword).")
+set(_PSTL_HIDE_FROM_ABI_PER_TU ${PSTL_HIDE_FROM_ABI_PER_TU}) # For __pstl_config_site
+
+if (NOT TBB_DIR)
+    get_filename_component(PSTL_DIR_NAME ${CMAKE_CURRENT_SOURCE_DIR} NAME)
+    string(REPLACE pstl tbb TBB_DIR_NAME ${PSTL_DIR_NAME})
+    if (EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/../${TBB_DIR_NAME}/cmake")
+        get_filename_component(TBB_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../${TBB_DIR_NAME}/cmake" ABSOLUTE)
+    endif()
+endif()
+
+###############################################################################
+# Setup the ParallelSTL library target
+###############################################################################
+add_library(ParallelSTL INTERFACE)
+add_library(pstl::ParallelSTL ALIAS ParallelSTL)
+target_compile_features(ParallelSTL INTERFACE cxx_std_17)
+
+if (PSTL_PARALLEL_BACKEND STREQUAL "serial")
+    message(STATUS "Parallel STL uses the serial backend")
+    set(_PSTL_PAR_BACKEND_SERIAL ON)
+elseif (PSTL_PARALLEL_BACKEND STREQUAL "tbb")
+    find_package(TBB 2018 REQUIRED tbb OPTIONAL_COMPONENTS tbbmalloc)
+    message(STATUS "Parallel STL uses TBB ${TBB_VERSION} (interface version: ${TBB_INTERFACE_VERSION})")
+    target_link_libraries(ParallelSTL INTERFACE TBB::tbb)
+    set(_PSTL_PAR_BACKEND_TBB ON)
+elseif (PSTL_PARALLEL_BACKEND STREQUAL "omp")
+    message(STATUS "Parallel STL uses the omp backend")
+    target_compile_options(ParallelSTL INTERFACE "-fopenmp=libomp")
+    set(_PSTL_PAR_BACKEND_OPENMP ON)
+else()
+    message(FATAL_ERROR "Requested unknown Parallel STL backend '${PSTL_PARALLEL_BACKEND}'.")
+endif()
+
+set(PSTL_GENERATED_HEADERS_DIR "${CMAKE_CURRENT_BINARY_DIR}/generated_headers")
+set(PSTL_CONFIG_SITE_PATH "${PSTL_GENERATED_HEADERS_DIR}/__pstl_config_site")
+configure_file("include/__pstl_config_site.in"
+               "${PSTL_CONFIG_SITE_PATH}"
+               @ONLY)
+
+target_include_directories(ParallelSTL
+    INTERFACE
+    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
+    $<BUILD_INTERFACE:${PSTL_GENERATED_HEADERS_DIR}>
+    $<INSTALL_INTERFACE:include>)
+
+###############################################################################
+# Setup tests
+###############################################################################
+enable_testing()
+add_subdirectory(test)
+
+###############################################################################
+# Install the target and the associated CMake files
+###############################################################################
+include(CMakePackageConfigHelpers)
+write_basic_package_version_file("${CMAKE_CURRENT_BINARY_DIR}/ParallelSTLConfigVersion.cmake"
+                                 COMPATIBILITY ExactVersion)
+
+configure_file(cmake/ParallelSTLConfig.cmake.in
+               "${CMAKE_CURRENT_BINARY_DIR}/ParallelSTLConfig.cmake"
+               @ONLY)
+
+install(TARGETS ParallelSTL
+        EXPORT ParallelSTLTargets)
+install(EXPORT ParallelSTLTargets
+        FILE ParallelSTLTargets.cmake
+        NAMESPACE pstl::
+        DESTINATION lib/cmake/ParallelSTL)
+install(FILES "${CMAKE_CURRENT_BINARY_DIR}/ParallelSTLConfig.cmake"
+              "${CMAKE_CURRENT_BINARY_DIR}/ParallelSTLConfigVersion.cmake"
+        DESTINATION lib/cmake/ParallelSTL)
+install(DIRECTORY include/
+        DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}"
+        PATTERN "*.in" EXCLUDE)
+install(FILES "${PSTL_CONFIG_SITE_PATH}"
+        DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}")
+
+add_custom_target(install-pstl
+                  COMMAND "${CMAKE_COMMAND}" -P "${PROJECT_BINARY_DIR}/cmake_install.cmake" -DCOMPONENT=ParallelSTL)
diff --git a/pstl/CREDITS.txt b/pstl/CREDITS.txt
new file mode 100644
index 0000000..4945fd5
--- /dev/null
+++ b/pstl/CREDITS.txt
@@ -0,0 +1,21 @@
+This file is a partial list of people who have contributed to the LLVM/pstl

+(Parallel STL) project.  If you have contributed a patch or made some other

+contribution to LLVM/pstl, please submit a patch to this file to add yourself,

+and it will be done!

+

+The list is sorted by surname and formatted to allow easy grepping and

+beautification by scripts.  The fields are: name (N), email (E), web-address 

+(W), PGP key ID and fingerprint (P), description (D), and snail-mail address

+(S).

+

+N: Intel Corporation

+W: http://www.intel.com

+D: Created the initial implementation.

+

+N: Thomas Rodgers

+E: trodgers@redhat.com

+D: Identifier name transformation for inclusion in a Standard C++ library.

+

+N: Christopher Nelson

+E: nadiasvertex@gmail.com

+D: Add support for an OpenMP backend.

diff --git a/pstl/LICENSE.TXT b/pstl/LICENSE.TXT
new file mode 100644
index 0000000..9eda544
--- /dev/null
+++ b/pstl/LICENSE.TXT
@@ -0,0 +1,307 @@
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+==============================================================================
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+The software contained in this directory tree is dual licensed under both the
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+you agree to allow your code to be used under both.
+
+Full text of the relevant licenses is included below.
+
+==============================================================================
+
+University of Illinois/NCSA
+Open Source License
+
+Copyright (c) 2017-2019 by the contributors listed in CREDITS.TXT
+
+All rights reserved.
+
+Developed by:
+    Threading Runtimes Team
+    Intel Corporation
+    http://www.intel.com
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal with
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+    * Redistributions of source code must retain the above copyright notice,
+      this list of conditions and the following disclaimers.
+
+    * Redistributions in binary form must reproduce the above copyright notice,
+      this list of conditions and the following disclaimers in the
+      documentation and/or other materials provided with the distribution.
+
+    * Neither the names of Intel Corporation Threading Runtimes Team nor the 
+      names of its contributors may be used to endorse or promote products 
+      derived from this Software without specific prior written permission.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
+SOFTWARE.
+
+==============================================================================
+
+Copyright (c) 2017-2019 by the contributors listed in CREDITS.TXT
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
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+THE SOFTWARE.
diff --git a/pstl/README.md b/pstl/README.md
new file mode 100644
index 0000000..5c862cb
--- /dev/null
+++ b/pstl/README.md
@@ -0,0 +1,35 @@
+# Parallel STL 
+
+Parallel STL is an implementation of the C++ standard library algorithms with support for execution policies,
+as specified in ISO/IEC 14882:2017 standard, commonly called C++17. The implementation also supports the unsequenced 
+execution policy specified in Parallelism TS version 2 and proposed for the next version of the C++ standard in the 
+C++ working group paper [P1001](https://wg21.link/p1001).
+Parallel STL offers efficient support for both parallel and vectorized execution of algorithms. For sequential 
+execution, it relies on an available implementation of the C++ standard library.
+
+## Prerequisites
+
+To use Parallel STL, you must have the following software installed:
+* C++ compiler with:
+  * Support for C++11
+  * Support for OpenMP* 4.0 SIMD constructs
+* Threading Building Blocks (TBB) which is available for download at https://github.com/01org/tbb/
+
+## Known issues and limitations
+
+* `unseq` and `par_unseq` policies only have effect with compilers that support `#pragma omp simd` or `#pragma simd`.
+* Parallel and vector execution is only supported for the algorithms if random access iterators are provided,
+  while for other iterator types the execution will remain serial.
+* The following algorithms do not allow efficient SIMD execution: `includes`, `inplace_merge`, `merge`, `nth_element`,
+  `partial_sort`, `partial_sort_copy`, `set_difference`, `set_intersection`, `set_symmetric_difference`, `set_union`,
+  `sort`, `stable_partition`, `stable_sort`, `unique`.
+* The initial value type for `exclusive_scan`, `inclusive_scan`, `transform_exclusive_scan`, `transform_inclusive_scan`
+  shall be DefaultConstructible. A default constructed-instance of the initial value type shall be the identity element
+  for the specified binary operation.
+* For `max_element`, `min_element`, `minmax_element`, `partial_sort`, `partial_sort_copy`, `sort`, `stable_sort`
+  the dereferenced value type of the provided iterators shall be DefaultConstructible.
+* For `remove`, `remove_if`, `unique` the dereferenced value type of the provided iterators shall be MoveConstructible.
+* The following algorithms require additional O(n) memory space for parallel execution: `copy_if`, `inplace_merge`,
+  `partial_sort`, `partial_sort_copy`, `partition_copy`, `remove`, `remove_if`, `rotate`, `sort`, `stable_sort`,
+  `unique`, `unique_copy`.
+
diff --git a/pstl/cmake/ParallelSTLConfig.cmake.in b/pstl/cmake/ParallelSTLConfig.cmake.in
new file mode 100644
index 0000000..445ebaf
--- /dev/null
+++ b/pstl/cmake/ParallelSTLConfig.cmake.in
@@ -0,0 +1,19 @@
+#===-- ParallelSTLConfig.cmake.in ----------------------------------------===##
+#
+# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+#
+#===----------------------------------------------------------------------===##
+
+include(CMakeFindDependencyMacro)
+
+set(PSTL_PARALLEL_BACKEND "@PSTL_PARALLEL_BACKEND@")
+
+if (PSTL_PARALLEL_BACKEND STREQUAL "tbb")
+    find_dependency(TBB REQUIRED tbb)
+endif()
+
+if (NOT TARGET pstl::ParallelSTL)
+    include("${CMAKE_CURRENT_LIST_DIR}/ParallelSTLTargets.cmake")
+endif()
diff --git a/pstl/docs/ReleaseNotes.rst b/pstl/docs/ReleaseNotes.rst
new file mode 100644
index 0000000..a0b3751
--- /dev/null
+++ b/pstl/docs/ReleaseNotes.rst
@@ -0,0 +1,40 @@
+=======================================
+PSTL 21.0.0 (In-Progress) Release Notes
+=======================================
+
+.. contents::
+   :local:
+   :depth: 2
+
+Written by the `PSTL Team <https://pstl.llvm.org>`_
+
+.. warning::
+
+   These are in-progress notes for the upcoming pstl 19 release.
+   Release notes for previous releases can be found on
+   `the Download Page <https://releases.llvm.org/download.html>`_.
+
+Introduction
+============
+
+This document contains the release notes for the PSTL parallel algorithms
+library, part of the LLVM Compiler Infrastructure, release 17.0.0. Here we
+describe the status of the library in some detail, including major improvements
+from the previous release and new feature work. For the general LLVM release
+notes, see `the LLVM documentation <https://llvm.org/docs/ReleaseNotes.html>`_.
+All LLVM releases may be downloaded from the `LLVM releases web site
+<https://llvm.org/releases/>`_.
+
+Note that if you are reading this file from a source checkout or the main PSTL
+web page, this document applies to the *next* release, not the current one.
+To see the release notes for a specific release, please see the `releases
+page <https://llvm.org/releases/>`_.
+
+What's New in PSTL 19.0.0?
+==========================
+
+New Features
+------------
+
+API Changes
+-----------
diff --git a/pstl/include/__pstl_algorithm b/pstl/include/__pstl_algorithm
new file mode 100644
index 0000000..79c1838
--- /dev/null
+++ b/pstl/include/__pstl_algorithm
@@ -0,0 +1,15 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __PSTL_ALGORITHM
+#define __PSTL_ALGORITHM
+
+#include <pstl/internal/glue_algorithm_impl.h>
+
+#endif /* __PSTL_ALGORITHM */
diff --git a/pstl/include/__pstl_config_site.in b/pstl/include/__pstl_config_site.in
new file mode 100644
index 0000000..a41a1c3
--- /dev/null
+++ b/pstl/include/__pstl_config_site.in
@@ -0,0 +1,17 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __PSTL_CONFIG_SITE
+#define __PSTL_CONFIG_SITE
+
+#cmakedefine _PSTL_PAR_BACKEND_SERIAL
+#cmakedefine _PSTL_PAR_BACKEND_TBB
+#cmakedefine _PSTL_PAR_BACKEND_OPENMP
+#cmakedefine _PSTL_HIDE_FROM_ABI_PER_TU
+
+#endif // __PSTL_CONFIG_SITE
diff --git a/pstl/include/__pstl_execution b/pstl/include/__pstl_execution
new file mode 100644
index 0000000..0e2cd44
--- /dev/null
+++ b/pstl/include/__pstl_execution
@@ -0,0 +1,15 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __PSTL_EXECUTION
+#define __PSTL_EXECUTION
+
+#include <pstl/internal/glue_execution_defs.h>
+
+#endif /* __PSTL_EXECUTION */
diff --git a/pstl/include/__pstl_memory b/pstl/include/__pstl_memory
new file mode 100644
index 0000000..12b7f5a
--- /dev/null
+++ b/pstl/include/__pstl_memory
@@ -0,0 +1,15 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __PSTL_MEMORY
+#define __PSTL_MEMORY
+
+#include <pstl/internal/glue_memory_impl.h>
+
+#endif /* __PSTL_MEMORY */
diff --git a/pstl/include/__pstl_numeric b/pstl/include/__pstl_numeric
new file mode 100644
index 0000000..cf168ef7
--- /dev/null
+++ b/pstl/include/__pstl_numeric
@@ -0,0 +1,15 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __PSTL_NUMERIC
+#define __PSTL_NUMERIC
+
+#include <pstl/internal/glue_numeric_impl.h>
+
+#endif /* __PSTL_NUMERIC */
diff --git a/pstl/include/pstl/internal/algorithm_fwd.h b/pstl/include/pstl/internal/algorithm_fwd.h
new file mode 100644
index 0000000..3dcf9e9
--- /dev/null
+++ b/pstl/include/pstl/internal/algorithm_fwd.h
@@ -0,0 +1,1202 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_ALGORITHM_FWD_H
+#define _PSTL_ALGORITHM_FWD_H
+
+#include <iterator>
+#include <type_traits>
+#include <utility>
+
+#include "pstl_config.h"
+
+_PSTL_HIDE_FROM_ABI_PUSH
+
+namespace __pstl
+{
+namespace __internal
+{
+
+//------------------------------------------------------------------------
+// any_of
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _Pred>
+bool
+__brick_any_of(const _ForwardIterator, const _ForwardIterator, _Pred,
+               /*__is_vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _Pred>
+bool
+__brick_any_of(const _RandomAccessIterator, const _RandomAccessIterator, _Pred,
+               /*__is_vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _Pred>
+bool
+__pattern_any_of(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, _Pred) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Pred>
+bool
+__pattern_any_of(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator, _Pred);
+
+//------------------------------------------------------------------------
+// walk1 (pseudo)
+//
+// walk1 evaluates f(x) for each dereferenced value x drawn from [first,last)
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _Function>
+void __brick_walk1(_ForwardIterator, _ForwardIterator, _Function,
+                   /*vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _Function>
+void __brick_walk1(_RandomAccessIterator, _RandomAccessIterator, _Function,
+                   /*vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _Function>
+void
+__pattern_walk1(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, _Function) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Function>
+void
+__pattern_walk1(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator, _Function);
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _Brick>
+void
+__pattern_walk_brick(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, _Brick) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Brick>
+void
+__pattern_walk_brick(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                     _Brick);
+
+//------------------------------------------------------------------------
+// walk1_n
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _Size, class _Function>
+_ForwardIterator __brick_walk1_n(_ForwardIterator, _Size, _Function,
+                                 /*_IsVectorTag=*/std::false_type);
+
+template <class _RandomAccessIterator, class _DifferenceType, class _Function>
+_RandomAccessIterator __brick_walk1_n(_RandomAccessIterator, _DifferenceType, _Function,
+                                      /*vectorTag=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Function>
+_ForwardIterator
+__pattern_walk1_n(_Tag, _ExecutionPolicy&&, _ForwardIterator, _Size, _Function) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Size, class _Function>
+_RandomAccessIterator
+__pattern_walk1_n(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _Size, _Function);
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Brick>
+_ForwardIterator
+__pattern_walk_brick_n(_Tag, _ExecutionPolicy&&, _ForwardIterator, _Size, _Brick) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Size, class _Brick>
+_RandomAccessIterator
+__pattern_walk_brick_n(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _Size, _Brick);
+
+//------------------------------------------------------------------------
+// walk2 (pseudo)
+//
+// walk2 evaluates f(x,y) for deferenced values (x,y) drawn from [first1,last1) and [first2,...)
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _Function>
+_ForwardIterator2 __brick_walk2(_ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _Function,
+                                /*vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _Function>
+_RandomAccessIterator2 __brick_walk2(_RandomAccessIterator1, _RandomAccessIterator1, _RandomAccessIterator2, _Function,
+                                     /*vector=*/std::true_type) noexcept;
+
+template <class _ForwardIterator1, class _Size, class _ForwardIterator2, class _Function>
+_ForwardIterator2 __brick_walk2_n(_ForwardIterator1, _Size, _ForwardIterator2, _Function,
+                                  /*vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator1, class _Size, class _RandomAccessIterator2, class _Function>
+_RandomAccessIterator2 __brick_walk2_n(_RandomAccessIterator1, _Size, _RandomAccessIterator2, _Function,
+                                       /*vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Function>
+_ForwardIterator2
+__pattern_walk2(_Tag, _ExecutionPolicy&&, _ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _Function) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _Function>
+_RandomAccessIterator2
+__pattern_walk2(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator1, _RandomAccessIterator1,
+                _RandomAccessIterator2, _Function);
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _Size, class _ForwardIterator2,
+          class _Function>
+_ForwardIterator2
+__pattern_walk2_n(_Tag, _ExecutionPolicy&&, _ForwardIterator1, _Size, _ForwardIterator2, _Function) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _Size,
+          class _RandomAccessIterator2, class _Function>
+_RandomAccessIterator2
+__pattern_walk2_n(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator1, _Size, _RandomAccessIterator2,
+                  _Function);
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Brick>
+_ForwardIterator2
+__pattern_walk2_brick(_Tag, _ExecutionPolicy&&, _ForwardIterator1, _ForwardIterator1, _ForwardIterator2,
+                      _Brick) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _Brick>
+_RandomAccessIterator2
+__pattern_walk2_brick(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator1, _RandomAccessIterator1,
+                      _RandomAccessIterator2, _Brick);
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _Size, class _ForwardIterator2,
+          class _Brick>
+_ForwardIterator2
+__pattern_walk2_brick_n(_Tag, _ExecutionPolicy&&, _ForwardIterator1, _Size, _ForwardIterator2, _Brick) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _Size,
+          class _RandomAccessIterator2, class _Brick>
+_RandomAccessIterator2
+__pattern_walk2_brick_n(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator1, _Size,
+                        _RandomAccessIterator2, _Brick);
+
+//------------------------------------------------------------------------
+// walk3 (pseudo)
+//
+// walk3 evaluates f(x,y,z) for (x,y,z) drawn from [first1,last1), [first2,...), [first3,...)
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator3, class _Function>
+_ForwardIterator3 __brick_walk3(_ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _ForwardIterator3, _Function,
+                                /*vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _RandomAccessIterator3, class _Function>
+_RandomAccessIterator3 __brick_walk3(_RandomAccessIterator1, _RandomAccessIterator1, _RandomAccessIterator2,
+                                     _RandomAccessIterator3, _Function,
+                                     /*vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator3,
+          class _Function>
+_ForwardIterator3
+__pattern_walk3(_Tag, _ExecutionPolicy&&, _ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _ForwardIterator3,
+                _Function) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _RandomAccessIterator3, class _Function>
+_RandomAccessIterator3
+__pattern_walk3(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator1, _RandomAccessIterator1,
+                _RandomAccessIterator2, _RandomAccessIterator3, _Function);
+
+//------------------------------------------------------------------------
+// equal
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+bool __brick_equal(_ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _BinaryPredicate,
+                   /* is_vector = */ std::false_type) noexcept;
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _BinaryPredicate>
+bool __brick_equal(_RandomAccessIterator1, _RandomAccessIterator1, _RandomAccessIterator2, _BinaryPredicate,
+                   /* is_vector = */ std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+bool
+__pattern_equal(_Tag, _ExecutionPolicy&&, _ForwardIterator1, _ForwardIterator1, _ForwardIterator2,
+                _BinaryPredicate) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _BinaryPredicate>
+bool
+__pattern_equal(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator1, _RandomAccessIterator1,
+                _RandomAccessIterator2, _BinaryPredicate);
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+bool __brick_equal(_ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _ForwardIterator2, _BinaryPredicate,
+                   /* is_vector = */ std::false_type) noexcept;
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _BinaryPredicate>
+bool __brick_equal(_RandomAccessIterator1, _RandomAccessIterator1, _RandomAccessIterator2, _RandomAccessIterator2,
+                   _BinaryPredicate, /* is_vector = */ std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+bool
+__pattern_equal(_Tag, _ExecutionPolicy&&, _ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _ForwardIterator2,
+                _BinaryPredicate) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _BinaryPredicate>
+bool
+__pattern_equal(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator1, _RandomAccessIterator1,
+                _RandomAccessIterator2, _RandomAccessIterator2, _BinaryPredicate);
+
+//------------------------------------------------------------------------
+// find_if
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _Predicate>
+_ForwardIterator __brick_find_if(_ForwardIterator, _ForwardIterator, _Predicate,
+                                 /*is_vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _Predicate>
+_RandomAccessIterator __brick_find_if(_RandomAccessIterator, _RandomAccessIterator, _Predicate,
+                                      /*is_vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _Predicate>
+_ForwardIterator
+__pattern_find_if(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, _Predicate) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Predicate>
+_RandomAccessIterator
+__pattern_find_if(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                  _Predicate);
+
+//------------------------------------------------------------------------
+// find_end
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_ForwardIterator1 __brick_find_end(_ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _ForwardIterator2,
+                                   _BinaryPredicate,
+                                   /*__is_vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _BinaryPredicate>
+_RandomAccessIterator1 __brick_find_end(_RandomAccessIterator1, _RandomAccessIterator1, _RandomAccessIterator2,
+                                        _RandomAccessIterator2, _BinaryPredicate,
+                                        /*__is_vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_ForwardIterator1
+__pattern_find_end(_Tag, _ExecutionPolicy&&, _ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _ForwardIterator2,
+                   _BinaryPredicate) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _BinaryPredicate>
+_RandomAccessIterator1
+__pattern_find_end(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator1, _RandomAccessIterator1,
+                   _RandomAccessIterator2, _RandomAccessIterator2, _BinaryPredicate) noexcept;
+
+//------------------------------------------------------------------------
+// find_first_of
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_ForwardIterator1 __brick_find_first_of(_ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _ForwardIterator2,
+                                        _BinaryPredicate,
+                                        /*__is_vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _BinaryPredicate>
+_RandomAccessIterator1 __brick_find_first_of(_RandomAccessIterator1, _RandomAccessIterator1, _RandomAccessIterator2,
+                                             _RandomAccessIterator2, _BinaryPredicate,
+                                             /*__is_vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_ForwardIterator1
+__pattern_find_first_of(_Tag, _ExecutionPolicy&&, _ForwardIterator1, _ForwardIterator1, _ForwardIterator2,
+                        _ForwardIterator2, _BinaryPredicate) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _BinaryPredicate>
+_RandomAccessIterator1
+__pattern_find_first_of(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator1, _RandomAccessIterator1,
+                        _RandomAccessIterator2, _RandomAccessIterator2, _BinaryPredicate) noexcept;
+
+//------------------------------------------------------------------------
+// search
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_ForwardIterator1 __brick_search(_ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _ForwardIterator2,
+                                 _BinaryPredicate,
+                                 /*vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _BinaryPredicate>
+_RandomAccessIterator1 __brick_search(_RandomAccessIterator1, _RandomAccessIterator1, _RandomAccessIterator2,
+                                      _RandomAccessIterator2, _BinaryPredicate,
+                                      /*vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_ForwardIterator1
+__pattern_search(_Tag, _ExecutionPolicy&&, _ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _ForwardIterator2,
+                 _BinaryPredicate) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _BinaryPredicate>
+_RandomAccessIterator1
+__pattern_search(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator1, _RandomAccessIterator1,
+                 _RandomAccessIterator2, _RandomAccessIterator2, _BinaryPredicate) noexcept;
+
+//------------------------------------------------------------------------
+// search_n
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _Size, class _Tp, class _BinaryPredicate>
+_ForwardIterator
+__brick_search_n(_ForwardIterator, _ForwardIterator, _Size, const _Tp&, _BinaryPredicate,
+                 /*vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _Size, class _Tp, class _BinaryPredicate>
+_RandomAccessIterator
+__brick_search_n(_RandomAccessIterator, _RandomAccessIterator, _Size, const _Tp&, _BinaryPredicate,
+                 /*vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Tp, class _BinaryPredicate>
+_ForwardIterator
+__pattern_search_n(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, _Size, const _Tp&,
+                   _BinaryPredicate) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Size, class _Tp,
+          class _BinaryPredicate>
+_RandomAccessIterator
+__pattern_search_n(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator, _Size,
+                   const _Tp&, _BinaryPredicate) noexcept;
+
+//------------------------------------------------------------------------
+// copy_n
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _Size, class _OutputIterator>
+_OutputIterator __brick_copy_n(_ForwardIterator, _Size, _OutputIterator,
+                               /*vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _Size, class _OutputIterator>
+_OutputIterator __brick_copy_n(_RandomAccessIterator, _Size, _OutputIterator,
+                               /*vector=*/std::true_type) noexcept;
+
+//------------------------------------------------------------------------
+// copy
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _OutputIterator>
+_OutputIterator __brick_copy(_ForwardIterator, _ForwardIterator, _OutputIterator,
+                             /*vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _OutputIterator>
+_OutputIterator __brick_copy(_RandomAccessIterator, _RandomAccessIterator, _OutputIterator,
+                             /*vector=*/std::true_type) noexcept;
+
+//------------------------------------------------------------------------
+// move
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _OutputIterator>
+_OutputIterator __brick_move(_ForwardIterator, _ForwardIterator, _OutputIterator,
+                             /*vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _OutputIterator>
+_OutputIterator __brick_move(_RandomAccessIterator, _RandomAccessIterator, _OutputIterator,
+                             /*vector=*/std::true_type) noexcept;
+
+//------------------------------------------------------------------------
+// swap_ranges
+//------------------------------------------------------------------------
+template <class _ForwardIterator, class _OutputIterator>
+_OutputIterator __brick_swap_ranges(_ForwardIterator, _ForwardIterator, _OutputIterator,
+                                    /*vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _OutputIterator>
+_OutputIterator __brick_swap_ranges(_RandomAccessIterator, _RandomAccessIterator, _OutputIterator,
+                                    /*vector=*/std::true_type) noexcept;
+
+//------------------------------------------------------------------------
+// copy_if
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _OutputIterator, class _UnaryPredicate>
+_OutputIterator __brick_copy_if(_ForwardIterator, _ForwardIterator, _OutputIterator, _UnaryPredicate,
+                                /*vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _OutputIterator, class _UnaryPredicate>
+_OutputIterator __brick_copy_if(_RandomAccessIterator, _RandomAccessIterator, _OutputIterator, _UnaryPredicate,
+                                /*vector=*/std::true_type) noexcept;
+
+template <class _DifferenceType, class _ForwardIterator, class _UnaryPredicate>
+std::pair<_DifferenceType, _DifferenceType>
+__brick_calc_mask_1(_ForwardIterator, _ForwardIterator, bool* __restrict, _UnaryPredicate,
+                    /*vector=*/std::false_type) noexcept;
+template <class _DifferenceType, class _RandomAccessIterator, class _UnaryPredicate>
+std::pair<_DifferenceType, _DifferenceType>
+__brick_calc_mask_1(_RandomAccessIterator, _RandomAccessIterator, bool* __restrict, _UnaryPredicate,
+                    /*vector=*/std::true_type) noexcept;
+
+template <class _ForwardIterator, class _OutputIterator>
+void
+__brick_copy_by_mask(_ForwardIterator, _ForwardIterator, _OutputIterator, bool*,
+                     /*vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _OutputIterator>
+void
+__brick_copy_by_mask(_RandomAccessIterator, _RandomAccessIterator, _OutputIterator, bool* __restrict,
+                     /*vector=*/std::true_type) noexcept;
+
+template <class _ForwardIterator, class _OutputIterator1, class _OutputIterator2>
+void
+__brick_partition_by_mask(_ForwardIterator, _ForwardIterator, _OutputIterator1, _OutputIterator2, bool*,
+                          /*vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _OutputIterator1, class _OutputIterator2>
+void
+__brick_partition_by_mask(_RandomAccessIterator, _RandomAccessIterator, _OutputIterator1, _OutputIterator2, bool*,
+                          /*vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _OutputIterator, class _UnaryPredicate>
+_OutputIterator
+__pattern_copy_if(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, _OutputIterator,
+                  _UnaryPredicate) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _OutputIterator,
+          class _UnaryPredicate>
+_OutputIterator
+__pattern_copy_if(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                  _OutputIterator, _UnaryPredicate);
+
+//------------------------------------------------------------------------
+// count
+//------------------------------------------------------------------------
+
+template <class _RandomAccessIterator, class _Predicate>
+typename std::iterator_traits<_RandomAccessIterator>::difference_type
+    __brick_count(_RandomAccessIterator, _RandomAccessIterator, _Predicate,
+                  /* is_vector = */ std::true_type) noexcept;
+
+template <class _ForwardIterator, class _Predicate>
+typename std::iterator_traits<_ForwardIterator>::difference_type
+    __brick_count(_ForwardIterator, _ForwardIterator, _Predicate,
+                  /* is_vector = */ std::false_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _Predicate>
+typename std::iterator_traits<_ForwardIterator>::difference_type
+__pattern_count(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, _Predicate) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Predicate>
+typename std::iterator_traits<_RandomAccessIterator>::difference_type
+__pattern_count(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                _Predicate);
+
+//------------------------------------------------------------------------
+// unique
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _BinaryPredicate>
+_ForwardIterator __brick_unique(_ForwardIterator, _ForwardIterator, _BinaryPredicate,
+                                /*is_vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _BinaryPredicate>
+_RandomAccessIterator __brick_unique(_RandomAccessIterator, _RandomAccessIterator, _BinaryPredicate,
+                                     /*is_vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _BinaryPredicate>
+_ForwardIterator
+__pattern_unique(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, _BinaryPredicate) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _BinaryPredicate>
+_RandomAccessIterator
+__pattern_unique(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                 _BinaryPredicate) noexcept;
+
+//------------------------------------------------------------------------
+// unique_copy
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class OutputIterator, class _BinaryPredicate>
+OutputIterator __brick_unique_copy(_ForwardIterator, _ForwardIterator, OutputIterator, _BinaryPredicate,
+                                   /*vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _OutputIterator, class _BinaryPredicate>
+_OutputIterator __brick_unique_copy(_RandomAccessIterator, _RandomAccessIterator, _OutputIterator, _BinaryPredicate,
+                                    /*vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _OutputIterator, class _BinaryPredicate>
+_OutputIterator
+__pattern_unique_copy(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, _OutputIterator,
+                      _BinaryPredicate) noexcept;
+
+template <class _ExecutionPolicy, class _DifferenceType, class _RandomAccessIterator, class _BinaryPredicate>
+_DifferenceType
+__brick_calc_mask_2(_RandomAccessIterator, _RandomAccessIterator, bool* __restrict, _BinaryPredicate,
+                    /*vector=*/std::false_type) noexcept;
+
+template <class _DifferenceType, class _RandomAccessIterator, class _BinaryPredicate>
+_DifferenceType
+__brick_calc_mask_2(_RandomAccessIterator, _RandomAccessIterator, bool* __restrict, _BinaryPredicate,
+                    /*vector=*/std::true_type) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _OutputIterator,
+          class _BinaryPredicate>
+_OutputIterator
+__pattern_unique_copy(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                      _OutputIterator, _BinaryPredicate);
+
+//------------------------------------------------------------------------
+// reverse
+//------------------------------------------------------------------------
+
+template <class _BidirectionalIterator>
+void __brick_reverse(_BidirectionalIterator, _BidirectionalIterator,
+                     /*__is_vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator>
+void __brick_reverse(_RandomAccessIterator, _RandomAccessIterator,
+                     /*__is_vector=*/std::true_type) noexcept;
+
+template <class _BidirectionalIterator>
+void __brick_reverse(_BidirectionalIterator, _BidirectionalIterator, _BidirectionalIterator,
+                     /*is_vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator>
+void __brick_reverse(_RandomAccessIterator, _RandomAccessIterator, _RandomAccessIterator,
+                     /*is_vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _BidirectionalIterator>
+void
+__pattern_reverse(_Tag, _ExecutionPolicy&&, _BidirectionalIterator, _BidirectionalIterator) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator>
+void
+__pattern_reverse(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator);
+
+//------------------------------------------------------------------------
+// reverse_copy
+//------------------------------------------------------------------------
+
+template <class _BidirectionalIterator, class _OutputIterator>
+_OutputIterator __brick_reverse_copy(_BidirectionalIterator, _BidirectionalIterator, _OutputIterator,
+                                     /*is_vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _OutputIterator>
+_OutputIterator __brick_reverse_copy(_RandomAccessIterator, _RandomAccessIterator, _OutputIterator,
+                                     /*is_vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _BidirectionalIterator, class _OutputIterator>
+_OutputIterator
+__pattern_reverse_copy(_Tag, _ExecutionPolicy&&, _BidirectionalIterator, _BidirectionalIterator,
+                       _OutputIterator) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _OutputIterator>
+_OutputIterator
+__pattern_reverse_copy(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                       _OutputIterator);
+
+//------------------------------------------------------------------------
+// rotate
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator>
+_ForwardIterator __brick_rotate(_ForwardIterator, _ForwardIterator, _ForwardIterator,
+                                /*is_vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator>
+_RandomAccessIterator __brick_rotate(_RandomAccessIterator, _RandomAccessIterator, _RandomAccessIterator,
+                                     /*is_vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator>
+_ForwardIterator
+__pattern_rotate(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, _ForwardIterator) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator>
+_RandomAccessIterator
+__pattern_rotate(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                 _RandomAccessIterator);
+
+//------------------------------------------------------------------------
+// rotate_copy
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _OutputIterator>
+_OutputIterator __brick_rotate_copy(_ForwardIterator, _ForwardIterator, _ForwardIterator, _OutputIterator,
+                                    /*__is_vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _OutputIterator>
+_OutputIterator __brick_rotate_copy(_RandomAccessIterator, _RandomAccessIterator, _RandomAccessIterator,
+                                    _OutputIterator,
+                                    /*__is_vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _OutputIterator>
+_OutputIterator
+__pattern_rotate_copy(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, _ForwardIterator,
+                      _OutputIterator) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _OutputIterator>
+_OutputIterator
+__pattern_rotate_copy(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                      _RandomAccessIterator, _OutputIterator);
+
+//------------------------------------------------------------------------
+// is_partitioned
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _UnaryPredicate>
+bool __brick_is_partitioned(_ForwardIterator, _ForwardIterator, _UnaryPredicate,
+                            /*is_vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _UnaryPredicate>
+bool __brick_is_partitioned(_RandomAccessIterator, _RandomAccessIterator, _UnaryPredicate,
+                            /*is_vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _UnaryPredicate>
+bool
+__pattern_is_partitioned(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, _UnaryPredicate) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _UnaryPredicate>
+bool
+__pattern_is_partitioned(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                         _UnaryPredicate);
+
+//------------------------------------------------------------------------
+// partition
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _UnaryPredicate>
+_ForwardIterator __brick_partition(_ForwardIterator, _ForwardIterator, _UnaryPredicate,
+                                   /*is_vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _UnaryPredicate>
+_RandomAccessIterator __brick_partition(_RandomAccessIterator, _RandomAccessIterator, _UnaryPredicate,
+                                        /*is_vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _UnaryPredicate>
+_ForwardIterator
+__pattern_partition(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, _UnaryPredicate) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _UnaryPredicate>
+_RandomAccessIterator
+__pattern_partition(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                    _UnaryPredicate);
+
+//------------------------------------------------------------------------
+// stable_partition
+//------------------------------------------------------------------------
+
+template <class _BidirectionalIterator, class _UnaryPredicate>
+_BidirectionalIterator __brick_stable_partition(_BidirectionalIterator, _BidirectionalIterator, _UnaryPredicate,
+                                                /*__is_vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _UnaryPredicate>
+_RandomAccessIterator __brick_stable_partition(_RandomAccessIterator, _RandomAccessIterator, _UnaryPredicate,
+                                               /*__is_vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _BidirectionalIterator, class _UnaryPredicate>
+_BidirectionalIterator
+__pattern_stable_partition(_Tag, _ExecutionPolicy&&, _BidirectionalIterator, _BidirectionalIterator,
+                           _UnaryPredicate) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _UnaryPredicate>
+_RandomAccessIterator
+__pattern_stable_partition(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                           _UnaryPredicate) noexcept;
+
+//------------------------------------------------------------------------
+// partition_copy
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _OutputIterator1, class _OutputIterator2, class _UnaryPredicate>
+std::pair<_OutputIterator1, _OutputIterator2>
+    __brick_partition_copy(_ForwardIterator, _ForwardIterator, _OutputIterator1, _OutputIterator2, _UnaryPredicate,
+                           /*is_vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _OutputIterator1, class _OutputIterator2, class _UnaryPredicate>
+std::pair<_OutputIterator1, _OutputIterator2> __brick_partition_copy(_RandomAccessIterator, _RandomAccessIterator,
+                                                                     _OutputIterator1, _OutputIterator2,
+                                                                     _UnaryPredicate,
+                                                                     /*is_vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _OutputIterator1, class _OutputIterator2,
+          class _UnaryPredicate>
+std::pair<_OutputIterator1, _OutputIterator2>
+__pattern_partition_copy(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, _OutputIterator1,
+                         _OutputIterator2, _UnaryPredicate) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _OutputIterator1,
+          class _OutputIterator2, class _UnaryPredicate>
+std::pair<_OutputIterator1, _OutputIterator2>
+__pattern_partition_copy(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                         _OutputIterator1, _OutputIterator2, _UnaryPredicate);
+
+//------------------------------------------------------------------------
+// sort
+//------------------------------------------------------------------------
+
+template <class _Tag, class _ExecutionPolicy, class _RandomAccessIterator, class _Compare, class _IsMoveConstructible>
+void
+__pattern_sort(_Tag, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator, _Compare,
+               _IsMoveConstructible) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+void
+__pattern_sort(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator, _Compare,
+               /*is_move_constructible=*/std::true_type);
+
+//------------------------------------------------------------------------
+// stable_sort
+//------------------------------------------------------------------------
+
+template <class _Tag, class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+void
+__pattern_stable_sort(_Tag, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator, _Compare) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+void
+__pattern_stable_sort(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                      _Compare);
+
+//------------------------------------------------------------------------
+// partial_sort
+//------------------------------------------------------------------------
+
+template <class _Tag, class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+void
+__pattern_partial_sort(_Tag, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator, _RandomAccessIterator,
+                       _Compare) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+void
+__pattern_partial_sort(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                       _RandomAccessIterator, _Compare);
+
+//------------------------------------------------------------------------
+// partial_sort_copy
+//------------------------------------------------------------------------
+
+template <class _Tag, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _Compare>
+_RandomAccessIterator2
+__pattern_partial_sort_copy(_Tag, _ExecutionPolicy&&, _RandomAccessIterator1, _RandomAccessIterator1,
+                            _RandomAccessIterator2, _RandomAccessIterator2, _Compare) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _Compare>
+_RandomAccessIterator2
+__pattern_partial_sort_copy(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator1,
+                            _RandomAccessIterator1, _RandomAccessIterator2, _RandomAccessIterator2, _Compare);
+
+//------------------------------------------------------------------------
+// adjacent_find
+//------------------------------------------------------------------------
+
+template <class _RandomAccessIterator, class _BinaryPredicate>
+_RandomAccessIterator
+__brick_adjacent_find(_RandomAccessIterator, _RandomAccessIterator, _BinaryPredicate,
+                      /* IsVector = */ std::true_type, bool) noexcept;
+
+template <class _ForwardIterator, class _BinaryPredicate>
+_ForwardIterator
+__brick_adjacent_find(_ForwardIterator, _ForwardIterator, _BinaryPredicate,
+                      /* IsVector = */ std::false_type, bool) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _BinaryPredicate>
+_ForwardIterator
+__pattern_adjacent_find(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, _BinaryPredicate, bool) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _BinaryPredicate>
+_RandomAccessIterator
+__pattern_adjacent_find(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                        _BinaryPredicate, bool);
+
+//------------------------------------------------------------------------
+// nth_element
+//------------------------------------------------------------------------
+template <class _Tag, class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+void
+__pattern_nth_element(_Tag, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator, _RandomAccessIterator,
+                      _Compare) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+void
+__pattern_nth_element(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                      _RandomAccessIterator, _Compare) noexcept;
+
+//------------------------------------------------------------------------
+// fill, fill_n
+//------------------------------------------------------------------------
+template <class _RandomAccessIterator, class _Tp>
+void
+__brick_fill(_RandomAccessIterator, _RandomAccessIterator, const _Tp&,
+             /* __is_vector = */ std::true_type) noexcept;
+
+template <class _ForwardIterator, class _Tp>
+void
+__brick_fill(_ForwardIterator, _ForwardIterator, const _Tp&,
+             /* __is_vector = */ std::false_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _Tp>
+void
+__pattern_fill(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, const _Tp&) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Tp>
+_RandomAccessIterator
+__pattern_fill(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator, const _Tp&);
+
+template <class _RandomAccessIterator, class _Size, class _Tp>
+_RandomAccessIterator
+__brick_fill_n(_RandomAccessIterator, _Size, const _Tp&,
+               /* __is_vector = */ std::true_type) noexcept;
+
+template <class _OutputIterator, class _Size, class _Tp>
+_OutputIterator
+__brick_fill_n(_OutputIterator, _Size, const _Tp&,
+               /* __is_vector = */ std::false_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _OutputIterator, class _Size, class _Tp>
+_OutputIterator
+__pattern_fill_n(_Tag, _ExecutionPolicy&&, _OutputIterator, _Size, const _Tp&) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Size, class _Tp>
+_RandomAccessIterator
+__pattern_fill_n(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _Size, const _Tp&);
+
+//------------------------------------------------------------------------
+// generate, generate_n
+//------------------------------------------------------------------------
+
+template <class _RandomAccessIterator, class _Generator>
+void __brick_generate(_RandomAccessIterator, _RandomAccessIterator, _Generator,
+                      /* is_vector = */ std::true_type) noexcept;
+
+template <class _ForwardIterator, class _Generator>
+void __brick_generate(_ForwardIterator, _ForwardIterator, _Generator,
+                      /* is_vector = */ std::false_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _Generator>
+void
+__pattern_generate(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, _Generator) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Generator>
+_RandomAccessIterator
+__pattern_generate(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                   _Generator);
+
+template <class _RandomAccessIterator, class Size, class _Generator>
+_RandomAccessIterator __brick_generate_n(_RandomAccessIterator, Size, _Generator,
+                                         /* is_vector = */ std::true_type) noexcept;
+
+template <class OutputIterator, class Size, class _Generator>
+OutputIterator __brick_generate_n(OutputIterator, Size, _Generator,
+                                  /* is_vector = */ std::false_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class OutputIterator, class Size, class _Generator>
+OutputIterator
+__pattern_generate_n(_Tag, _ExecutionPolicy&&, OutputIterator, Size, _Generator) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class Size, class _Generator>
+_RandomAccessIterator
+__pattern_generate_n(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, Size, _Generator);
+
+//------------------------------------------------------------------------
+// remove
+//------------------------------------------------------------------------
+template <class _ForwardIterator, class _UnaryPredicate>
+_ForwardIterator __brick_remove_if(_ForwardIterator, _ForwardIterator, _UnaryPredicate,
+                                   /* __is_vector = */ std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _UnaryPredicate>
+_RandomAccessIterator __brick_remove_if(_RandomAccessIterator, _RandomAccessIterator, _UnaryPredicate,
+                                        /* __is_vector = */ std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _UnaryPredicate>
+_ForwardIterator
+__pattern_remove_if(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, _UnaryPredicate) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _UnaryPredicate>
+_RandomAccessIterator
+__pattern_remove_if(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                    _UnaryPredicate) noexcept;
+
+//------------------------------------------------------------------------
+// merge
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _OutputIterator, class _Compare>
+_OutputIterator __brick_merge(_ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _ForwardIterator2,
+                              _OutputIterator, _Compare,
+                              /* __is_vector = */ std::false_type) noexcept;
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _OutputIterator, class _Compare>
+_OutputIterator __brick_merge(_RandomAccessIterator1, _RandomAccessIterator1, _RandomAccessIterator2,
+                              _RandomAccessIterator2, _OutputIterator, _Compare,
+                              /* __is_vector = */ std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _OutputIterator,
+          class _Compare>
+_OutputIterator
+__pattern_merge(_Tag, _ExecutionPolicy&&, _ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _ForwardIterator2,
+                _OutputIterator, _Compare) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _OutputIterator, class _Compare>
+_OutputIterator
+__pattern_merge(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator1, _RandomAccessIterator1,
+                _RandomAccessIterator2, _RandomAccessIterator2, _OutputIterator, _Compare);
+
+//------------------------------------------------------------------------
+// inplace_merge
+//------------------------------------------------------------------------
+
+template <class _BidirectionalIterator, class _Compare>
+void __brick_inplace_merge(_BidirectionalIterator, _BidirectionalIterator, _BidirectionalIterator, _Compare,
+                           /* __is_vector = */ std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _Compare>
+void __brick_inplace_merge(_RandomAccessIterator, _RandomAccessIterator, _RandomAccessIterator, _Compare,
+                           /* __is_vector = */ std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _BidirectionalIterator, class _Compare>
+void
+__pattern_inplace_merge(_Tag, _ExecutionPolicy&&, _BidirectionalIterator, _BidirectionalIterator,
+                        _BidirectionalIterator, _Compare) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+void
+__pattern_inplace_merge(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                        _RandomAccessIterator, _Compare);
+
+//------------------------------------------------------------------------
+// includes
+//------------------------------------------------------------------------
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Compare>
+bool
+__pattern_includes(_Tag, _ExecutionPolicy&&, _ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _ForwardIterator2,
+                   _Compare) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _Compare>
+bool
+__pattern_includes(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator1, _RandomAccessIterator1,
+                   _RandomAccessIterator2, _RandomAccessIterator2, _Compare);
+
+//------------------------------------------------------------------------
+// set_union
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _OutputIterator, class _Compare>
+_OutputIterator __brick_set_union(_ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _ForwardIterator2,
+                                  _OutputIterator, _Compare,
+                                  /*__is_vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _OutputIterator, class _Compare>
+_OutputIterator __brick_set_union(_RandomAccessIterator1, _RandomAccessIterator1, _RandomAccessIterator2,
+                                  _RandomAccessIterator2, _OutputIterator, _Compare,
+                                  /*__is_vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _OutputIterator,
+          class _Compare>
+_OutputIterator
+__pattern_set_union(_Tag, _ExecutionPolicy&&, _ForwardIterator1, _ForwardIterator1, _ForwardIterator2,
+                    _ForwardIterator2, _OutputIterator, _Compare) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _OutputIterator, class _Compare>
+_OutputIterator
+__pattern_set_union(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator1, _RandomAccessIterator1,
+                    _RandomAccessIterator2, _RandomAccessIterator2, _OutputIterator, _Compare);
+
+//------------------------------------------------------------------------
+// set_intersection
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _OutputIterator, class _Compare>
+_OutputIterator __brick_set_intersection(_ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _ForwardIterator2,
+                                         _OutputIterator, _Compare,
+                                         /*__is_vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _OutputIterator, class _Compare>
+_OutputIterator __brick_set_intersection(_RandomAccessIterator1, _RandomAccessIterator1, _RandomAccessIterator2,
+                                         _RandomAccessIterator2, _OutputIterator, _Compare,
+                                         /*__is_vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _OutputIterator,
+          class _Compare>
+_OutputIterator
+__pattern_set_intersection(_Tag, _ExecutionPolicy&&, _ForwardIterator1, _ForwardIterator1, _ForwardIterator2,
+                           _ForwardIterator2, _OutputIterator, _Compare) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _OutputIterator, class _Compare>
+_OutputIterator
+__pattern_set_intersection(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator1,
+                           _RandomAccessIterator1, _RandomAccessIterator2, _RandomAccessIterator2, _OutputIterator,
+                           _Compare);
+
+//------------------------------------------------------------------------
+// set_difference
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _OutputIterator, class _Compare>
+_OutputIterator __brick_set_difference(_ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _ForwardIterator2,
+                                       _OutputIterator, _Compare,
+                                       /*__is_vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _OutputIterator, class _Compare>
+_OutputIterator __brick_set_difference(_RandomAccessIterator1, _RandomAccessIterator1, _RandomAccessIterator2,
+                                       _RandomAccessIterator2, _OutputIterator, _Compare,
+                                       /*__is_vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _OutputIterator,
+          class _Compare>
+_OutputIterator
+__pattern_set_difference(_Tag, _ExecutionPolicy&&, _ForwardIterator1, _ForwardIterator1, _ForwardIterator2,
+                         _ForwardIterator2, _OutputIterator, _Compare) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _OutputIterator, class _Compare>
+_OutputIterator
+__pattern_set_difference(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator1, _RandomAccessIterator1,
+                         _RandomAccessIterator2, _RandomAccessIterator2, _OutputIterator, _Compare);
+
+//------------------------------------------------------------------------
+// set_symmetric_difference
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _OutputIterator, class _Compare>
+_OutputIterator __brick_set_symmetric_difference(_ForwardIterator1, _ForwardIterator1, _ForwardIterator2,
+                                                 _ForwardIterator2, _OutputIterator, _Compare,
+                                                 /*__is_vector=*/std::false_type) noexcept;
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _OutputIterator, class _Compare>
+_OutputIterator __brick_set_symmetric_difference(_RandomAccessIterator1, _RandomAccessIterator1, _RandomAccessIterator2,
+                                                 _RandomAccessIterator2, _OutputIterator, _Compare,
+                                                 /*__is_vector=*/std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _OutputIterator,
+          class _Compare>
+_OutputIterator
+__pattern_set_symmetric_difference(_Tag, _ExecutionPolicy&&, _ForwardIterator1, _ForwardIterator1, _ForwardIterator2,
+                                   _ForwardIterator2, _OutputIterator, _Compare) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _OutputIterator, class _Compare>
+_OutputIterator
+__pattern_set_symmetric_difference(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator1,
+                                   _RandomAccessIterator1, _RandomAccessIterator2, _RandomAccessIterator2,
+                                   _OutputIterator, _Compare);
+
+//------------------------------------------------------------------------
+// is_heap_until
+//------------------------------------------------------------------------
+
+template <class _RandomAccessIterator, class _Compare>
+_RandomAccessIterator __brick_is_heap_until(_RandomAccessIterator, _RandomAccessIterator, _Compare,
+                                            /* __is_vector = */ std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _Compare>
+_RandomAccessIterator __brick_is_heap_until(_RandomAccessIterator, _RandomAccessIterator, _Compare,
+                                            /* __is_vector = */ std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+_RandomAccessIterator
+__pattern_is_heap_until(_Tag, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator, _Compare) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+_RandomAccessIterator
+__pattern_is_heap_until(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                        _Compare) noexcept;
+
+//------------------------------------------------------------------------
+// min_element
+//------------------------------------------------------------------------
+
+template <typename _ForwardIterator, typename _Compare>
+_ForwardIterator __brick_min_element(_ForwardIterator, _ForwardIterator, _Compare,
+                                     /* __is_vector = */ std::false_type) noexcept;
+
+template <typename _RandomAccessIterator, typename _Compare>
+_RandomAccessIterator __brick_min_element(_RandomAccessIterator, _RandomAccessIterator, _Compare,
+                                          /* __is_vector = */ std::true_type) noexcept;
+
+template <typename _Tag, typename _ExecutionPolicy, typename _ForwardIterator, typename _Compare>
+_ForwardIterator
+__pattern_min_element(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, _Compare) noexcept;
+
+template <typename _IsVector, typename _ExecutionPolicy, typename _RandomAccessIterator, typename _Compare>
+_RandomAccessIterator
+__pattern_min_element(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                      _Compare);
+
+//------------------------------------------------------------------------
+// minmax_element
+//------------------------------------------------------------------------
+
+template <typename _ForwardIterator, typename _Compare>
+std::pair<_ForwardIterator, _ForwardIterator> __brick_minmax_element(_ForwardIterator, _ForwardIterator, _Compare,
+                                                                     /* __is_vector = */ std::false_type) noexcept;
+
+template <typename _RandomAccessIterator, typename _Compare>
+std::pair<_RandomAccessIterator, _RandomAccessIterator>
+    __brick_minmax_element(_RandomAccessIterator, _RandomAccessIterator, _Compare,
+                           /* __is_vector = */ std::true_type) noexcept;
+
+template <typename _Tag, typename _ExecutionPolicy, typename _ForwardIterator, typename _Compare>
+std::pair<_ForwardIterator, _ForwardIterator>
+__pattern_minmax_element(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, _Compare) noexcept;
+
+template <typename _IsVector, typename _ExecutionPolicy, typename _RandomAccessIterator, typename _Compare>
+std::pair<_RandomAccessIterator, _RandomAccessIterator>
+__pattern_minmax_element(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                         _Compare);
+
+//------------------------------------------------------------------------
+// mismatch
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _Predicate>
+std::pair<_ForwardIterator1, _ForwardIterator2> __brick_mismatch(_ForwardIterator1, _ForwardIterator1,
+                                                                 _ForwardIterator2, _ForwardIterator2, _Predicate,
+                                                                 /* __is_vector = */ std::false_type) noexcept;
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _Predicate>
+std::pair<_RandomAccessIterator1, _RandomAccessIterator2>
+    __brick_mismatch(_RandomAccessIterator1, _RandomAccessIterator1, _RandomAccessIterator2, _RandomAccessIterator2,
+                     _Predicate,
+                     /* __is_vector = */ std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Predicate>
+std::pair<_ForwardIterator1, _ForwardIterator2>
+__pattern_mismatch(_Tag, _ExecutionPolicy&&, _ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _ForwardIterator2,
+                   _Predicate) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _Predicate>
+std::pair<_RandomAccessIterator1, _RandomAccessIterator2>
+__pattern_mismatch(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator1, _RandomAccessIterator1,
+                   _RandomAccessIterator2, _RandomAccessIterator2, _Predicate) noexcept;
+
+//------------------------------------------------------------------------
+// lexicographical_compare
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _Compare>
+bool __brick_lexicographical_compare(_ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _ForwardIterator2,
+                                     _Compare,
+                                     /* __is_vector = */ std::false_type) noexcept;
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _Compare>
+bool __brick_lexicographical_compare(_RandomAccessIterator1, _RandomAccessIterator1, _RandomAccessIterator2,
+                                     _RandomAccessIterator2, _Compare,
+                                     /* __is_vector = */ std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Compare>
+bool
+__pattern_lexicographical_compare(_Tag, _ExecutionPolicy&&, _ForwardIterator1, _ForwardIterator1, _ForwardIterator2,
+                                  _ForwardIterator2, _Compare) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _Compare>
+bool
+__pattern_lexicographical_compare(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator1,
+                                  _RandomAccessIterator1, _RandomAccessIterator2, _RandomAccessIterator2,
+                                  _Compare) noexcept;
+
+} // namespace __internal
+} // namespace __pstl
+
+_PSTL_HIDE_FROM_ABI_POP
+
+#endif /* _PSTL_ALGORITHM_FWD_H */
diff --git a/pstl/include/pstl/internal/algorithm_impl.h b/pstl/include/pstl/internal/algorithm_impl.h
new file mode 100644
index 0000000..2b505d9
--- /dev/null
+++ b/pstl/include/pstl/internal/algorithm_impl.h
@@ -0,0 +1,3819 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_ALGORITHM_IMPL_H
+#define _PSTL_ALGORITHM_IMPL_H
+
+#include <iterator>
+#include <type_traits>
+#include <utility>
+#include <functional>
+#include <algorithm>
+
+#include "execution_impl.h"
+#include "memory_impl.h"
+#include "parallel_backend.h"
+#include "parallel_backend_utils.h"
+#include "parallel_impl.h"
+#include "pstl_config.h"
+#include "unseq_backend_simd.h"
+
+_PSTL_HIDE_FROM_ABI_PUSH
+
+namespace __pstl
+{
+namespace __internal
+{
+
+//------------------------------------------------------------------------
+// any_of
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _Pred>
+bool
+__brick_any_of(const _ForwardIterator __first, const _ForwardIterator __last, _Pred __pred,
+               /*__is_vector=*/std::false_type) noexcept
+{
+    return std::any_of(__first, __last, __pred);
+};
+
+template <class _RandomAccessIterator, class _Pred>
+bool
+__brick_any_of(const _RandomAccessIterator __first, const _RandomAccessIterator __last, _Pred __pred,
+               /*__is_vector=*/std::true_type) noexcept
+{
+    return __unseq_backend::__simd_or(__first, __last - __first, __pred);
+};
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _Pred>
+bool
+__pattern_any_of(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last, _Pred __pred) noexcept
+{
+    return __internal::__brick_any_of(__first, __last, __pred, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Pred>
+bool
+__pattern_any_of(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                 _RandomAccessIterator __last, _Pred __pred)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    return __internal::__except_handler(
+        [&]()
+        {
+            return __internal::__parallel_or(__backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                             [__pred](_RandomAccessIterator __i, _RandomAccessIterator __j)
+                                             { return __internal::__brick_any_of(__i, __j, __pred, _IsVector{}); });
+        });
+}
+
+// [alg.foreach]
+// for_each_n with no policy
+
+template <class _ForwardIterator, class _Size, class _Function>
+_ForwardIterator
+__for_each_n_it_serial(_ForwardIterator __first, _Size __n, _Function __f)
+{
+    for (; __n > 0; ++__first, --__n)
+        __f(__first);
+    return __first;
+}
+
+//------------------------------------------------------------------------
+// walk1 (pseudo)
+//
+// walk1 evaluates f(x) for each dereferenced value x drawn from [first,last)
+//------------------------------------------------------------------------
+template <class _ForwardIterator, class _Function>
+void
+__brick_walk1(_ForwardIterator __first, _ForwardIterator __last, _Function __f, /*vector=*/std::false_type) noexcept
+{
+    std::for_each(__first, __last, __f);
+}
+
+template <class _RandomAccessIterator, class _Function>
+void
+__brick_walk1(_RandomAccessIterator __first, _RandomAccessIterator __last, _Function __f,
+              /*vector=*/std::true_type) noexcept
+{
+    __unseq_backend::__simd_walk_1(__first, __last - __first, __f);
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _Function>
+void
+__pattern_walk1(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last, _Function __f) noexcept
+{
+    __internal::__brick_walk1(__first, __last, __f, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Function>
+void
+__pattern_walk1(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                _RandomAccessIterator __last, _Function __f)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    __internal::__except_handler(
+        [&]()
+        {
+            __par_backend::__parallel_for(__backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                          [__f](_RandomAccessIterator __i, _RandomAccessIterator __j)
+                                          { __internal::__brick_walk1(__i, __j, __f, _IsVector{}); });
+        });
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _Brick>
+void
+__pattern_walk_brick(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last,
+                     _Brick __brick) noexcept
+{
+    __brick(__first, __last);
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Brick>
+void
+__pattern_walk_brick(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                     _RandomAccessIterator __last, _Brick __brick)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    __internal::__except_handler(
+        [&]()
+        {
+            __par_backend::__parallel_for(__backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                          [__brick](_RandomAccessIterator __i, _RandomAccessIterator __j)
+                                          { __brick(__i, __j); });
+        });
+}
+
+//------------------------------------------------------------------------
+// walk1_n
+//------------------------------------------------------------------------
+template <class _ForwardIterator, class _Size, class _Function>
+_ForwardIterator
+__brick_walk1_n(_ForwardIterator __first, _Size __n, _Function __f, /*_IsVectorTag=*/std::false_type)
+{
+    return __internal::__for_each_n_it_serial(__first, __n,
+                                              [&__f](_ForwardIterator __it) { __f(*__it); }); // calling serial version
+}
+
+template <class _RandomAccessIterator, class _DifferenceType, class _Function>
+_RandomAccessIterator
+__brick_walk1_n(_RandomAccessIterator __first, _DifferenceType __n, _Function __f,
+                /*vectorTag=*/std::true_type) noexcept
+{
+    return __unseq_backend::__simd_walk_1(__first, __n, __f);
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Function>
+_ForwardIterator
+__pattern_walk1_n(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _Size __n, _Function __f) noexcept
+{
+    return __internal::__brick_walk1_n(__first, __n, __f, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Size, class _Function>
+_RandomAccessIterator
+__pattern_walk1_n(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first, _Size __n,
+                  _Function __f)
+{
+    __internal::__pattern_walk1(__tag, std::forward<_ExecutionPolicy>(__exec), __first, __first + __n, __f);
+
+    return __first + __n;
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Brick>
+_ForwardIterator
+__pattern_walk_brick_n(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _Size __n, _Brick __brick) noexcept
+{
+    return __brick(__first, __n);
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Size, class _Brick>
+_RandomAccessIterator
+__pattern_walk_brick_n(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                       _Size __n, _Brick __brick)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    return __internal::__except_handler(
+        [&]()
+        {
+            __par_backend::__parallel_for(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __first + __n,
+                [__brick](_RandomAccessIterator __i, _RandomAccessIterator __j) { __brick(__i, __j - __i); });
+            return __first + __n;
+        });
+}
+
+//------------------------------------------------------------------------
+// walk2 (pseudo)
+//
+// walk2 evaluates f(x,y) for deferenced values (x,y) drawn from [first1,last1) and [first2,...)
+//------------------------------------------------------------------------
+template <class _ForwardIterator1, class _ForwardIterator2, class _Function>
+_ForwardIterator2
+__brick_walk2(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _Function __f,
+              /*vector=*/std::false_type) noexcept
+{
+    for (; __first1 != __last1; ++__first1, ++__first2)
+        __f(*__first1, *__first2);
+    return __first2;
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _Function>
+_RandomAccessIterator2
+__brick_walk2(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2,
+              _Function __f,
+              /*vector=*/std::true_type) noexcept
+{
+    return __unseq_backend::__simd_walk_2(__first1, __last1 - __first1, __first2, __f);
+}
+
+template <class _ForwardIterator1, class _Size, class _ForwardIterator2, class _Function>
+_ForwardIterator2
+__brick_walk2_n(_ForwardIterator1 __first1, _Size __n, _ForwardIterator2 __first2, _Function __f,
+                /*vector=*/std::false_type) noexcept
+{
+    for (; __n > 0; --__n, ++__first1, ++__first2)
+        __f(*__first1, *__first2);
+    return __first2;
+}
+
+template <class _RandomAccessIterator1, class _Size, class _RandomAccessIterator2, class _Function>
+_RandomAccessIterator2
+__brick_walk2_n(_RandomAccessIterator1 __first1, _Size __n, _RandomAccessIterator2 __first2, _Function __f,
+                /*vector=*/std::true_type) noexcept
+{
+    return __unseq_backend::__simd_walk_2(__first1, __n, __first2, __f);
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Function>
+_ForwardIterator2
+__pattern_walk2(_Tag, _ExecutionPolicy&&, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                _ForwardIterator2 __first2, _Function __f) noexcept
+{
+    return __internal::__brick_walk2(__first1, __last1, __first2, __f, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _Function>
+_RandomAccessIterator2
+__pattern_walk2(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first1,
+                _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2, _Function __f)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    return __internal::__except_handler(
+        [&]()
+        {
+            __par_backend::__parallel_for(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first1, __last1,
+                [__f, __first1, __first2](_RandomAccessIterator1 __i, _RandomAccessIterator1 __j)
+                { __internal::__brick_walk2(__i, __j, __first2 + (__i - __first1), __f, _IsVector{}); });
+            return __first2 + (__last1 - __first1);
+        });
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _Size, class _ForwardIterator2,
+          class _Function>
+_ForwardIterator2
+__pattern_walk2_n(_Tag, _ExecutionPolicy&&, _ForwardIterator1 __first1, _Size __n, _ForwardIterator2 __first2,
+                  _Function __f) noexcept
+{
+    return __internal::__brick_walk2_n(__first1, __n, __first2, __f, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _Size,
+          class _RandomAccessIterator2, class _Function>
+_RandomAccessIterator2
+__pattern_walk2_n(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first1,
+                  _Size __n, _RandomAccessIterator2 __first2, _Function __f)
+{
+    return __internal::__pattern_walk2(__tag, std::forward<_ExecutionPolicy>(__exec), __first1, __first1 + __n,
+                                       __first2, __f);
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Brick>
+_ForwardIterator2
+__pattern_walk2_brick(_Tag, _ExecutionPolicy&&, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                      _ForwardIterator2 __first2, _Brick __brick) noexcept
+{
+    return __brick(__first1, __last1, __first2);
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _Brick>
+_RandomAccessIterator2
+__pattern_walk2_brick(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first1,
+                      _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2, _Brick __brick)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    return __internal::__except_handler(
+        [&]()
+        {
+            __par_backend::__parallel_for(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first1, __last1,
+                [__first1, __first2, __brick](_RandomAccessIterator1 __i, _RandomAccessIterator1 __j)
+                { __brick(__i, __j, __first2 + (__i - __first1)); });
+            return __first2 + (__last1 - __first1);
+        });
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _Size, class _ForwardIterator2,
+          class _Brick>
+_ForwardIterator2
+__pattern_walk2_brick_n(_Tag, _ExecutionPolicy&&, _ForwardIterator1 __first1, _Size __n, _ForwardIterator2 __first2,
+                        _Brick __brick) noexcept
+{
+    return __brick(__first1, __n, __first2);
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _Size,
+          class _RandomAccessIterator2, class _Brick>
+_RandomAccessIterator2
+__pattern_walk2_brick_n(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first1,
+                        _Size __n, _RandomAccessIterator2 __first2, _Brick __brick)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    return __internal::__except_handler(
+        [&]()
+        {
+            __par_backend::__parallel_for(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first1, __first1 + __n,
+                [__first1, __first2, __brick](_RandomAccessIterator1 __i, _RandomAccessIterator1 __j)
+                { __brick(__i, __j - __i, __first2 + (__i - __first1)); });
+            return __first2 + __n;
+        });
+}
+
+//------------------------------------------------------------------------
+// walk3 (pseudo)
+//
+// walk3 evaluates f(x,y,z) for (x,y,z) drawn from [first1,last1), [first2,...), [first3,...)
+//------------------------------------------------------------------------
+template <class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator3, class _Function>
+_ForwardIterator3
+__brick_walk3(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+              _ForwardIterator3 __first3, _Function __f, /*vector=*/std::false_type) noexcept
+{
+    for (; __first1 != __last1; ++__first1, ++__first2, ++__first3)
+        __f(*__first1, *__first2, *__first3);
+    return __first3;
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _RandomAccessIterator3, class _Function>
+_RandomAccessIterator3
+__brick_walk3(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2,
+              _RandomAccessIterator3 __first3, _Function __f, /*vector=*/std::true_type) noexcept
+{
+    return __unseq_backend::__simd_walk_3(__first1, __last1 - __first1, __first2, __first3, __f);
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator3,
+          class _Function>
+_ForwardIterator3
+__pattern_walk3(_Tag, _ExecutionPolicy&&, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                _ForwardIterator2 __first2, _ForwardIterator3 __first3, _Function __f) noexcept
+{
+    return __internal::__brick_walk3(__first1, __last1, __first2, __first3, __f, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _RandomAccessIterator3, class _Function>
+_RandomAccessIterator3
+__pattern_walk3(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first1,
+                _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2, _RandomAccessIterator3 __first3,
+                _Function __f)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    return __internal::__except_handler(
+        [&]()
+        {
+            __par_backend::__parallel_for(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first1, __last1,
+                [__f, __first1, __first2, __first3](_RandomAccessIterator1 __i, _RandomAccessIterator1 __j) {
+                    __internal::__brick_walk3(__i, __j, __first2 + (__i - __first1), __first3 + (__i - __first1), __f,
+                                              _IsVector{});
+                });
+            return __first3 + (__last1 - __first1);
+        });
+}
+
+//------------------------------------------------------------------------
+// equal
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+bool
+__brick_equal(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+              _ForwardIterator2 __last2, _BinaryPredicate __p, /* IsVector = */ std::false_type) noexcept
+{
+    return std::equal(__first1, __last1, __first2, __last2, __p);
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _BinaryPredicate>
+bool
+__brick_equal(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2,
+              _RandomAccessIterator2 __last2, _BinaryPredicate __p, /* is_vector = */ std::true_type) noexcept
+{
+    if (__last1 - __first1 != __last2 - __first2)
+        return false;
+
+    return __unseq_backend::__simd_first(__first1, __last1 - __first1, __first2, std::not_fn(__p)).first == __last1;
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+bool
+__pattern_equal(_Tag, _ExecutionPolicy&&, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __p) noexcept
+{
+    return __internal::__brick_equal(__first1, __last1, __first2, __last2, __p, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _BinaryPredicate>
+bool
+__pattern_equal(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first1,
+                _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2,
+                _BinaryPredicate __p)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    if (__last1 - __first1 != __last2 - __first2)
+        return false;
+
+    return __internal::__except_handler(
+        [&]()
+        {
+            return !__internal::__parallel_or(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first1, __last1,
+                [__first1, __first2, __p](_RandomAccessIterator1 __i, _RandomAccessIterator1 __j)
+                {
+                    return !__internal::__brick_equal(__i, __j, __first2 + (__i - __first1),
+                                                      __first2 + (__j - __first1), __p, _IsVector{});
+                });
+        });
+}
+
+//------------------------------------------------------------------------
+// equal version for sequences with equal length
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+bool
+__brick_equal(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _BinaryPredicate __p,
+              /* IsVector = */ std::false_type) noexcept
+{
+    return std::equal(__first1, __last1, __first2, __p);
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _BinaryPredicate>
+bool
+__brick_equal(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2,
+              _BinaryPredicate __p, /* is_vector = */ std::true_type) noexcept
+{
+    return __unseq_backend::__simd_first(__first1, __last1 - __first1, __first2, std::not_fn(__p)).first == __last1;
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+bool
+__pattern_equal(_Tag, _ExecutionPolicy&&, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                _ForwardIterator2 __first2, _BinaryPredicate __p) noexcept
+{
+    return __internal::__brick_equal(__first1, __last1, __first2, __p, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _BinaryPredicate>
+bool
+__pattern_equal(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first1,
+                _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2, _BinaryPredicate __p)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    return __internal::__except_handler(
+        [&]()
+        {
+            return !__internal::__parallel_or(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first1, __last1,
+                [__first1, __first2, __p](_RandomAccessIterator1 __i, _RandomAccessIterator1 __j)
+                { return !__internal::__brick_equal(__i, __j, __first2 + (__i - __first1), __p, _IsVector{}); });
+        });
+}
+
+//------------------------------------------------------------------------
+// find_if
+//------------------------------------------------------------------------
+template <class _ForwardIterator, class _Predicate>
+_ForwardIterator
+__brick_find_if(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred,
+                /*is_vector=*/std::false_type) noexcept
+{
+    return std::find_if(__first, __last, __pred);
+}
+
+template <class _RandomAccessIterator, class _Predicate>
+_RandomAccessIterator
+__brick_find_if(_RandomAccessIterator __first, _RandomAccessIterator __last, _Predicate __pred,
+                /*is_vector=*/std::true_type) noexcept
+{
+    typedef typename std::iterator_traits<_RandomAccessIterator>::difference_type _SizeType;
+    return __unseq_backend::__simd_first(
+        __first, _SizeType(0), __last - __first,
+        [&__pred](_RandomAccessIterator __it, _SizeType __i) { return __pred(__it[__i]); });
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _Predicate>
+_ForwardIterator
+__pattern_find_if(_Tag __tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last,
+                  _Predicate __pred) noexcept
+{
+    return __internal::__brick_find_if(__first, __last, __pred, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Predicate>
+_RandomAccessIterator
+__pattern_find_if(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                  _RandomAccessIterator __last, _Predicate __pred)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    return __internal::__except_handler(
+        [&]()
+        {
+            return __internal::__parallel_find(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                [__pred](_RandomAccessIterator __i, _RandomAccessIterator __j)
+                { return __internal::__brick_find_if(__i, __j, __pred, _IsVector{}); },
+                std::less<typename std::iterator_traits<_RandomAccessIterator>::difference_type>(),
+                /*is_first=*/true);
+        });
+}
+
+//------------------------------------------------------------------------
+// find_end
+//------------------------------------------------------------------------
+
+// find the first occurrence of the subsequence [s_first, s_last)
+//   or the  last occurrence of the subsequence in the range [first, last)
+// b_first determines what occurrence we want to find (first or last)
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _BinaryPredicate, class _IsVector>
+_RandomAccessIterator1
+__find_subrange(_RandomAccessIterator1 __first, _RandomAccessIterator1 __last, _RandomAccessIterator1 __global_last,
+                _RandomAccessIterator2 __s_first, _RandomAccessIterator2 __s_last, _BinaryPredicate __pred,
+                bool __b_first, _IsVector __is_vector) noexcept
+{
+    typedef typename std::iterator_traits<_RandomAccessIterator2>::value_type _ValueType;
+    auto __n2 = __s_last - __s_first;
+    if (__n2 < 1)
+    {
+        return __b_first ? __first : __last;
+    }
+
+    auto __n1 = __global_last - __first;
+    if (__n1 < __n2)
+    {
+        return __last;
+    }
+
+    auto __cur = __last;
+    while (__first != __last && (__global_last - __first >= __n2))
+    {
+        // find position of *s_first in [first, last) (it can be start of subsequence)
+        __first = __internal::__brick_find_if(
+            __first, __last, __equal_value_by_pred<_ValueType, _BinaryPredicate>(*__s_first, __pred), __is_vector);
+
+        // if position that was found previously is the start of subsequence
+        // then we can exit the loop (b_first == true) or keep the position
+        // (b_first == false)
+        if (__first != __last && (__global_last - __first >= __n2) &&
+            __internal::__brick_equal(__s_first + 1, __s_last, __first + 1, __pred, __is_vector))
+        {
+            if (__b_first)
+            {
+                return __first;
+            }
+            else
+            {
+                __cur = __first;
+            }
+        }
+        else if (__first == __last)
+        {
+            break;
+        }
+        else
+        {
+        }
+
+        // in case of b_first == false we try to find new start position
+        // for the next subsequence
+        ++__first;
+    }
+    return __cur;
+}
+
+template <class _RandomAccessIterator, class _Size, class _Tp, class _BinaryPredicate, class _IsVector>
+_RandomAccessIterator
+__find_subrange(_RandomAccessIterator __first, _RandomAccessIterator __last, _RandomAccessIterator __global_last,
+                _Size __count, const _Tp& __value, _BinaryPredicate __pred, _IsVector __is_vector) noexcept
+{
+    if (static_cast<_Size>(__global_last - __first) < __count || __count < 1)
+    {
+        return __last; // According to the standard last shall be returned when count < 1
+    }
+
+    auto __unary_pred = __equal_value_by_pred<_Tp, _BinaryPredicate>(__value, __pred);
+    while (__first != __last && (static_cast<_Size>(__global_last - __first) >= __count))
+    {
+        __first = __internal::__brick_find_if(__first, __last, __unary_pred, __is_vector);
+
+        // check that all of elements in [first+1, first+count) equal to value
+        if (__first != __last && (static_cast<_Size>(__global_last - __first) >= __count) &&
+            !__internal::__brick_any_of(__first + 1, __first + __count, std::not_fn(__unary_pred), __is_vector))
+        {
+            return __first;
+        }
+        else if (__first == __last)
+        {
+            break;
+        }
+        else
+        {
+            ++__first;
+        }
+    }
+    return __last;
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_ForwardIterator1
+__brick_find_end(_ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __s_first,
+                 _ForwardIterator2 __s_last, _BinaryPredicate __pred, /*__is_vector=*/std::false_type) noexcept
+{
+    return std::find_end(__first, __last, __s_first, __s_last, __pred);
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _BinaryPredicate>
+_RandomAccessIterator1
+__brick_find_end(_RandomAccessIterator1 __first, _RandomAccessIterator1 __last, _RandomAccessIterator2 __s_first,
+                 _RandomAccessIterator2 __s_last, _BinaryPredicate __pred, /*__is_vector=*/std::true_type) noexcept
+{
+    return __find_subrange(__first, __last, __last, __s_first, __s_last, __pred, false, std::true_type());
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_ForwardIterator1
+__pattern_find_end(_Tag, _ExecutionPolicy&&, _ForwardIterator1 __first, _ForwardIterator1 __last,
+                   _ForwardIterator2 __s_first, _ForwardIterator2 __s_last, _BinaryPredicate __pred) noexcept
+{
+    return __internal::__brick_find_end(__first, __last, __s_first, __s_last, __pred, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _BinaryPredicate>
+_RandomAccessIterator1
+__pattern_find_end(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first,
+                   _RandomAccessIterator1 __last, _RandomAccessIterator2 __s_first, _RandomAccessIterator2 __s_last,
+                   _BinaryPredicate __pred) noexcept
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    if (__last - __first == __s_last - __s_first)
+    {
+        const bool __res = __internal::__pattern_equal(__tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                                       __s_first, __pred);
+        return __res ? __first : __last;
+    }
+    else
+    {
+        return __internal::__except_handler(
+            [&]()
+            {
+                return __internal::__parallel_find(
+                    __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                    [__last, __s_first, __s_last, __pred](_RandomAccessIterator1 __i, _RandomAccessIterator1 __j) {
+                        return __internal::__find_subrange(__i, __j, __last, __s_first, __s_last, __pred, false,
+                                                           _IsVector{});
+                    },
+                    std::greater<typename std::iterator_traits<_RandomAccessIterator1>::difference_type>(),
+                    /*is_first=*/false);
+            });
+    }
+}
+
+//------------------------------------------------------------------------
+// find_first_of
+//------------------------------------------------------------------------
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_ForwardIterator1
+__brick_find_first_of(_ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __s_first,
+                      _ForwardIterator2 __s_last, _BinaryPredicate __pred, /*__is_vector=*/std::false_type) noexcept
+{
+    return std::find_first_of(__first, __last, __s_first, __s_last, __pred);
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _BinaryPredicate>
+_RandomAccessIterator1
+__brick_find_first_of(_RandomAccessIterator1 __first, _RandomAccessIterator1 __last, _RandomAccessIterator2 __s_first,
+                      _RandomAccessIterator2 __s_last, _BinaryPredicate __pred, /*__is_vector=*/std::true_type) noexcept
+{
+    return __unseq_backend::__simd_find_first_of(__first, __last, __s_first, __s_last, __pred);
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_ForwardIterator1
+__pattern_find_first_of(_Tag, _ExecutionPolicy&&, _ForwardIterator1 __first, _ForwardIterator1 __last,
+                        _ForwardIterator2 __s_first, _ForwardIterator2 __s_last, _BinaryPredicate __pred) noexcept
+{
+    return __internal::__brick_find_first_of(__first, __last, __s_first, __s_last, __pred,
+                                             typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _BinaryPredicate>
+_RandomAccessIterator1
+__pattern_find_first_of(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first,
+                        _RandomAccessIterator1 __last, _RandomAccessIterator2 __s_first,
+                        _RandomAccessIterator2 __s_last, _BinaryPredicate __pred) noexcept
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    return __internal::__except_handler(
+        [&]()
+        {
+            return __internal::__parallel_find(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                [__s_first, __s_last, __pred](_RandomAccessIterator1 __i, _RandomAccessIterator1 __j)
+                { return __internal::__brick_find_first_of(__i, __j, __s_first, __s_last, __pred, _IsVector{}); },
+                std::less<typename std::iterator_traits<_RandomAccessIterator1>::difference_type>(), /*is_first=*/true);
+        });
+}
+
+//------------------------------------------------------------------------
+// search
+//------------------------------------------------------------------------
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _BinaryPredicate>
+_RandomAccessIterator1
+__brick_search(_RandomAccessIterator1 __first, _RandomAccessIterator1 __last, _RandomAccessIterator2 __s_first,
+               _RandomAccessIterator2 __s_last, _BinaryPredicate __pred, /*vector=*/std::false_type) noexcept
+{
+    return std::search(__first, __last, __s_first, __s_last, __pred);
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _BinaryPredicate>
+_RandomAccessIterator1
+__brick_search(_RandomAccessIterator1 __first, _RandomAccessIterator1 __last, _RandomAccessIterator2 __s_first,
+               _RandomAccessIterator2 __s_last, _BinaryPredicate __pred, /*vector=*/std::true_type) noexcept
+{
+    return __internal::__find_subrange(__first, __last, __last, __s_first, __s_last, __pred, true, std::true_type());
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_ForwardIterator1
+__pattern_search(_Tag, _ExecutionPolicy&&, _ForwardIterator1 __first, _ForwardIterator1 __last,
+                 _ForwardIterator2 __s_first, _ForwardIterator2 __s_last, _BinaryPredicate __pred) noexcept
+{
+    return __internal::__brick_search(__first, __last, __s_first, __s_last, __pred, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _BinaryPredicate>
+_RandomAccessIterator1
+__pattern_search(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first,
+                 _RandomAccessIterator1 __last, _RandomAccessIterator2 __s_first, _RandomAccessIterator2 __s_last,
+                 _BinaryPredicate __pred) noexcept
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    if (__last - __first == __s_last - __s_first)
+    {
+        const bool __res = __internal::__pattern_equal(__tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                                       __s_first, __pred);
+        return __res ? __first : __last;
+    }
+    else
+    {
+        return __internal::__except_handler(
+            [&]()
+            {
+                return __internal::__parallel_find(
+                    __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                    [__last, __s_first, __s_last, __pred](_RandomAccessIterator1 __i, _RandomAccessIterator1 __j) {
+                        return __internal::__find_subrange(__i, __j, __last, __s_first, __s_last, __pred, true,
+                                                           _IsVector{});
+                    },
+                    std::less<typename std::iterator_traits<_RandomAccessIterator1>::difference_type>(),
+                    /*is_first=*/true);
+            });
+    }
+}
+
+//------------------------------------------------------------------------
+// search_n
+//------------------------------------------------------------------------
+template <class _ForwardIterator, class _Size, class _Tp, class _BinaryPredicate>
+_ForwardIterator
+__brick_search_n(_ForwardIterator __first, _ForwardIterator __last, _Size __count, const _Tp& __value,
+                 _BinaryPredicate __pred, /*vector=*/std::false_type) noexcept
+{
+    return std::search_n(__first, __last, __count, __value, __pred);
+}
+
+template <class _RandomAccessIterator, class _Size, class _Tp, class _BinaryPredicate>
+_RandomAccessIterator
+__brick_search_n(_RandomAccessIterator __first, _RandomAccessIterator __last, _Size __count, const _Tp& __value,
+                 _BinaryPredicate __pred, /*vector=*/std::true_type) noexcept
+{
+    return __internal::__find_subrange(__first, __last, __last, __count, __value, __pred, std::true_type());
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Tp, class _BinaryPredicate>
+_ForwardIterator
+__pattern_search_n(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last, _Size __count,
+                   const _Tp& __value, _BinaryPredicate __pred) noexcept
+{
+    return __internal::__brick_search_n(__first, __last, __count, __value, __pred, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Size, class _Tp,
+          class _BinaryPredicate>
+_RandomAccessIterator
+__pattern_search_n(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                   _RandomAccessIterator __last, _Size __count, const _Tp& __value, _BinaryPredicate __pred) noexcept
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    if (static_cast<_Size>(__last - __first) == __count)
+    {
+        const bool __result =
+            !__internal::__pattern_any_of(__tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                          [&__value, &__pred](const _Tp& __val) { return !__pred(__val, __value); });
+        return __result ? __first : __last;
+    }
+    else
+    {
+        return __internal::__except_handler(
+            [&__exec, __first, __last, __count, &__value, __pred]()
+            {
+                return __internal::__parallel_find(
+                    __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                    [__last, __count, &__value, __pred](_RandomAccessIterator __i, _RandomAccessIterator __j)
+                    { return __internal::__find_subrange(__i, __j, __last, __count, __value, __pred, _IsVector{}); },
+                    std::less<typename std::iterator_traits<_RandomAccessIterator>::difference_type>(),
+                    /*is_first=*/true);
+            });
+    }
+}
+
+//------------------------------------------------------------------------
+// copy_n
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _Size, class _OutputIterator>
+_OutputIterator
+__brick_copy_n(_ForwardIterator __first, _Size __n, _OutputIterator __result, /*vector=*/std::false_type) noexcept
+{
+    return std::copy_n(__first, __n, __result);
+}
+
+template <class _RandomAccessIterator1, class _Size, class _RandomAccessIterator2>
+_RandomAccessIterator2
+__brick_copy_n(_RandomAccessIterator1 __first, _Size __n, _RandomAccessIterator2 __result,
+               /*vector=*/std::true_type) noexcept
+{
+    return __unseq_backend::__simd_assign(
+        __first, __n, __result,
+        [](_RandomAccessIterator1 __first, _RandomAccessIterator2 __result) { *__result = *__first; });
+}
+
+//------------------------------------------------------------------------
+// copy
+//------------------------------------------------------------------------
+template <class _ForwardIterator, class _OutputIterator>
+_OutputIterator
+__brick_copy(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator __result,
+             /*vector=*/std::false_type) noexcept
+{
+    return std::copy(__first, __last, __result);
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2>
+_RandomAccessIterator2
+__brick_copy(_RandomAccessIterator1 __first, _RandomAccessIterator1 __last, _RandomAccessIterator2 __result,
+             /*vector=*/std::true_type) noexcept
+{
+    return __unseq_backend::__simd_assign(
+        __first, __last - __first, __result,
+        [](_RandomAccessIterator1 __first, _RandomAccessIterator2 __result) { *__result = *__first; });
+}
+
+//------------------------------------------------------------------------
+// move
+//------------------------------------------------------------------------
+template <class _ForwardIterator, class _OutputIterator>
+_OutputIterator
+__brick_move(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator __result,
+             /*vector=*/std::false_type) noexcept
+{
+    return std::move(__first, __last, __result);
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2>
+_RandomAccessIterator2
+__brick_move(_RandomAccessIterator1 __first, _RandomAccessIterator1 __last, _RandomAccessIterator2 __result,
+             /*vector=*/std::true_type) noexcept
+{
+    return __unseq_backend::__simd_assign(
+        __first, __last - __first, __result,
+        [](_RandomAccessIterator1 __first, _RandomAccessIterator2 __result) { *__result = std::move(*__first); });
+}
+
+struct __brick_move_destroy
+{
+    template <typename _RandomAccessIterator1, typename _RandomAccessIterator2>
+    _RandomAccessIterator2
+    operator()(_RandomAccessIterator1 __first, _RandomAccessIterator1 __last, _RandomAccessIterator2 __result,
+               /*vec*/ std::true_type) const
+    {
+        using _IteratorValueType = typename std::iterator_traits<_RandomAccessIterator1>::value_type;
+
+        return __unseq_backend::__simd_assign(__first, __last - __first, __result,
+                                              [](_RandomAccessIterator1 __first, _RandomAccessIterator2 __result) {
+                                                  *__result = std::move(*__first);
+                                                  (*__first).~_IteratorValueType();
+                                              });
+    }
+
+    template <typename _RandomAccessIterator1, typename _RandomAccessIterator2>
+    _RandomAccessIterator2
+    operator()(_RandomAccessIterator1 __first, _RandomAccessIterator1 __last, _RandomAccessIterator2 __result,
+               /*vec*/ std::false_type) const
+    {
+        using _IteratorValueType = typename std::iterator_traits<_RandomAccessIterator1>::value_type;
+
+        for (; __first != __last; ++__first, ++__result)
+        {
+            *__result = std::move(*__first);
+            (*__first).~_IteratorValueType();
+        }
+        return __result;
+    }
+};
+
+//------------------------------------------------------------------------
+// swap_ranges
+//------------------------------------------------------------------------
+template <class _ForwardIterator, class _OutputIterator>
+_OutputIterator
+__brick_swap_ranges(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator __result,
+                    /*vector=*/std::false_type) noexcept
+{
+    return std::swap_ranges(__first, __last, __result);
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2>
+_RandomAccessIterator2
+__brick_swap_ranges(_RandomAccessIterator1 __first, _RandomAccessIterator1 __last, _RandomAccessIterator2 __result,
+                    /*vector=*/std::true_type) noexcept
+{
+    using std::iter_swap;
+    return __unseq_backend::__simd_assign(__first, __last - __first, __result,
+                                          iter_swap<_RandomAccessIterator1, _RandomAccessIterator2>);
+}
+
+//------------------------------------------------------------------------
+// copy_if
+//------------------------------------------------------------------------
+template <class _ForwardIterator, class _OutputIterator, class _UnaryPredicate>
+_OutputIterator
+__brick_copy_if(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator __result, _UnaryPredicate __pred,
+                /*vector=*/std::false_type) noexcept
+{
+    return std::copy_if(__first, __last, __result, __pred);
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _UnaryPredicate>
+_RandomAccessIterator2
+__brick_copy_if(_RandomAccessIterator1 __first, _RandomAccessIterator1 __last, _RandomAccessIterator2 __result,
+                _UnaryPredicate __pred,
+                /*vector=*/std::true_type) noexcept
+{
+#if defined(_PSTL_MONOTONIC_PRESENT)
+    return __unseq_backend::__simd_copy_if(__first, __last - __first, __result, __pred);
+#else
+    return std::copy_if(__first, __last, __result, __pred);
+#endif
+}
+
+// TODO: Try to use transform_reduce for combining __brick_copy_if_phase1 on IsVector.
+template <class _DifferenceType, class _ForwardIterator, class _UnaryPredicate>
+std::pair<_DifferenceType, _DifferenceType>
+__brick_calc_mask_1(_ForwardIterator __first, _ForwardIterator __last, bool* __restrict __mask, _UnaryPredicate __pred,
+                    /*vector=*/std::false_type) noexcept
+{
+    auto __count_true = _DifferenceType(0);
+    auto __size = __last - __first;
+
+    static_assert(__are_random_access_iterators<_ForwardIterator>::value,
+                  "Pattern-brick error. Should be a random access iterator.");
+
+    for (; __first != __last; ++__first, ++__mask)
+    {
+        *__mask = __pred(*__first);
+        if (*__mask)
+        {
+            ++__count_true;
+        }
+    }
+    return std::make_pair(__count_true, __size - __count_true);
+}
+
+template <class _DifferenceType, class _RandomAccessIterator, class _UnaryPredicate>
+std::pair<_DifferenceType, _DifferenceType>
+__brick_calc_mask_1(_RandomAccessIterator __first, _RandomAccessIterator __last, bool* __mask, _UnaryPredicate __pred,
+                    /*vector=*/std::true_type) noexcept
+{
+    auto __result = __unseq_backend::__simd_calc_mask_1(__first, __last - __first, __mask, __pred);
+    return std::make_pair(__result, (__last - __first) - __result);
+}
+
+template <class _ForwardIterator, class _OutputIterator, class _Assigner>
+void
+__brick_copy_by_mask(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator __result, bool* __mask,
+                     _Assigner __assigner, /*vector=*/std::false_type) noexcept
+{
+    for (; __first != __last; ++__first, ++__mask)
+    {
+        if (*__mask)
+        {
+            __assigner(__first, __result);
+            ++__result;
+        }
+    }
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _Assigner>
+void
+__brick_copy_by_mask(_RandomAccessIterator1 __first, _RandomAccessIterator1 __last, _RandomAccessIterator2 __result,
+                     bool* __restrict __mask, _Assigner __assigner, /*vector=*/std::true_type) noexcept
+{
+#if defined(_PSTL_MONOTONIC_PRESENT)
+    __unseq_backend::__simd_copy_by_mask(__first, __last - __first, __result, __mask, __assigner);
+#else
+    __internal::__brick_copy_by_mask(__first, __last, __result, __mask, __assigner, std::false_type());
+#endif
+}
+
+template <class _ForwardIterator, class _OutputIterator1, class _OutputIterator2>
+void
+__brick_partition_by_mask(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator1 __out_true,
+                          _OutputIterator2 __out_false, bool* __mask, /*vector=*/std::false_type) noexcept
+{
+    for (; __first != __last; ++__first, ++__mask)
+    {
+        if (*__mask)
+        {
+            *__out_true = *__first;
+            ++__out_true;
+        }
+        else
+        {
+            *__out_false = *__first;
+            ++__out_false;
+        }
+    }
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _RandomAccessIterator3>
+void
+__brick_partition_by_mask(_RandomAccessIterator1 __first, _RandomAccessIterator1 __last,
+                          _RandomAccessIterator2 __out_true, _RandomAccessIterator3 __out_false, bool* __mask,
+                          /*vector=*/std::true_type) noexcept
+{
+#if defined(_PSTL_MONOTONIC_PRESENT)
+    __unseq_backend::__simd_partition_by_mask(__first, __last - __first, __out_true, __out_false, __mask);
+#else
+    __internal::__brick_partition_by_mask(__first, __last, __out_true, __out_false, __mask, std::false_type());
+#endif
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _OutputIterator, class _UnaryPredicate>
+_OutputIterator
+__pattern_copy_if(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last, _OutputIterator __result,
+                  _UnaryPredicate __pred) noexcept
+{
+    return __internal::__brick_copy_if(__first, __last, __result, __pred, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _UnaryPredicate>
+_RandomAccessIterator2
+__pattern_copy_if(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first,
+                  _RandomAccessIterator1 __last, _RandomAccessIterator2 __result, _UnaryPredicate __pred)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    typedef typename std::iterator_traits<_RandomAccessIterator1>::difference_type _DifferenceType;
+    const _DifferenceType __n = __last - __first;
+    if (_DifferenceType(1) < __n)
+    {
+        __par_backend::__buffer<bool> __mask_buf(__n);
+        return __internal::__except_handler(
+            [&__exec, __n, __first, __result, __pred, &__mask_buf]()
+            {
+                bool* __mask = __mask_buf.get();
+                _DifferenceType __m{};
+                __par_backend::__parallel_strict_scan(
+                    __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __n, _DifferenceType(0),
+                    [=](_DifferenceType __i, _DifferenceType __len) { // Reduce
+                        return __internal::__brick_calc_mask_1<_DifferenceType>(__first + __i, __first + (__i + __len),
+                                                                                __mask + __i, __pred, _IsVector{})
+                            .first;
+                    },
+                    std::plus<_DifferenceType>(),                                                // Combine
+                    [=](_DifferenceType __i, _DifferenceType __len, _DifferenceType __initial) { // Scan
+                        __internal::__brick_copy_by_mask(
+                            __first + __i, __first + (__i + __len), __result + __initial, __mask + __i,
+                            [](_RandomAccessIterator1 __x, _RandomAccessIterator2 __z) { *__z = *__x; }, _IsVector{});
+                    },
+                    [&__m](_DifferenceType __total) { __m = __total; });
+                return __result + __m;
+            });
+    }
+    // trivial sequence - use serial algorithm
+    return __internal::__brick_copy_if(__first, __last, __result, __pred, _IsVector{});
+}
+
+//------------------------------------------------------------------------
+// count
+//------------------------------------------------------------------------
+template <class _RandomAccessIterator, class _Predicate>
+typename std::iterator_traits<_RandomAccessIterator>::difference_type
+__brick_count(_RandomAccessIterator __first, _RandomAccessIterator __last, _Predicate __pred,
+              /* is_vector = */ std::true_type) noexcept
+{
+    return __unseq_backend::__simd_count(__first, __last - __first, __pred);
+}
+
+template <class _ForwardIterator, class _Predicate>
+typename std::iterator_traits<_ForwardIterator>::difference_type
+__brick_count(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred,
+              /* is_vector = */ std::false_type) noexcept
+{
+    return std::count_if(__first, __last, __pred);
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _Predicate>
+typename std::iterator_traits<_ForwardIterator>::difference_type
+__pattern_count(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) noexcept
+{
+    return __internal::__brick_count(__first, __last, __pred, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Predicate>
+typename std::iterator_traits<_RandomAccessIterator>::difference_type
+__pattern_count(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                _RandomAccessIterator __last, _Predicate __pred)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    typedef typename std::iterator_traits<_RandomAccessIterator>::difference_type _SizeType;
+    return __internal::__except_handler(
+        [&]()
+        {
+            return __par_backend::__parallel_reduce(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last, _SizeType(0),
+                [__pred](_RandomAccessIterator __begin, _RandomAccessIterator __end, _SizeType __value) -> _SizeType
+                { return __value + __internal::__brick_count(__begin, __end, __pred, _IsVector{}); },
+                std::plus<_SizeType>());
+        });
+}
+
+//------------------------------------------------------------------------
+// unique
+//------------------------------------------------------------------------
+
+template <class _RandomAccessIterator, class _BinaryPredicate>
+_RandomAccessIterator
+__brick_unique(_RandomAccessIterator __first, _RandomAccessIterator __last, _BinaryPredicate __pred,
+               /*is_vector=*/std::false_type) noexcept
+{
+    return std::unique(__first, __last, __pred);
+}
+
+template <class _RandomAccessIterator, class _BinaryPredicate>
+_RandomAccessIterator
+__brick_unique(_RandomAccessIterator __first, _RandomAccessIterator __last, _BinaryPredicate __pred,
+               /*is_vector=*/std::true_type) noexcept
+{
+    _PSTL_PRAGMA_MESSAGE("Vectorized algorithm unimplemented, redirected to serial");
+    return std::unique(__first, __last, __pred);
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _BinaryPredicate>
+_ForwardIterator
+__pattern_unique(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last,
+                 _BinaryPredicate __pred) noexcept
+{
+    return __internal::__brick_unique(__first, __last, __pred, typename _Tag::__is_vector{});
+}
+
+// That function is shared between two algorithms - remove_if (__pattern_remove_if) and unique (pattern unique). But a mask calculation is different.
+// So, a caller passes _CalcMask brick into remove_elements.
+template <class _IsVector, class _ExecutionPolicy, class _ForwardIterator, class _CalcMask>
+_ForwardIterator
+__remove_elements(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _ForwardIterator __first,
+                  _ForwardIterator __last, _CalcMask __calc_mask)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    typedef typename std::iterator_traits<_ForwardIterator>::difference_type _DifferenceType;
+    typedef typename std::iterator_traits<_ForwardIterator>::value_type _Tp;
+    _DifferenceType __n = __last - __first;
+    __par_backend::__buffer<bool> __mask_buf(__n);
+    // 1. find a first iterator that should be removed
+    return __internal::__except_handler([&]() {
+        bool* __mask = __mask_buf.get();
+        _DifferenceType __min = __par_backend::__parallel_reduce(
+            __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), _DifferenceType(0), __n, __n,
+            [__first, __mask, &__calc_mask](_DifferenceType __i, _DifferenceType __j,
+                                            _DifferenceType __local_min) -> _DifferenceType
+            {
+                // Create mask
+                __calc_mask(__mask + __i, __mask + __j, __first + __i);
+
+                // if minimum was found in a previous range we shouldn't do anymore
+                if (__local_min < __i)
+                {
+                    return __local_min;
+                }
+                // find first iterator that should be removed
+                bool* __result = __internal::__brick_find_if(
+                    __mask + __i, __mask + __j, [](bool __val) { return !__val; }, _IsVector{});
+                if (__result - __mask == __j)
+                {
+                    return __local_min;
+                }
+                return std::min(__local_min, _DifferenceType(__result - __mask));
+            },
+            [](_DifferenceType __local_min1, _DifferenceType __local_min2) -> _DifferenceType
+            { return std::min(__local_min1, __local_min2); });
+
+        // No elements to remove - exit
+        if (__min == __n)
+        {
+            return __last;
+        }
+        __n -= __min;
+        __first += __min;
+
+        __par_backend::__buffer<_Tp> __buf(__n);
+        _Tp* __result = __buf.get();
+        __mask += __min;
+        _DifferenceType __m{};
+        // 2. Elements that doesn't satisfy pred are moved to result
+        __par_backend::__parallel_strict_scan(
+            __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __n, _DifferenceType(0),
+            [__mask](_DifferenceType __i, _DifferenceType __len)
+            {
+                return __internal::__brick_count(
+                    __mask + __i, __mask + __i + __len, [](bool __val) { return __val; }, _IsVector{});
+            },
+            std::plus<_DifferenceType>(),
+            [=](_DifferenceType __i, _DifferenceType __len, _DifferenceType __initial)
+            {
+                __internal::__brick_copy_by_mask(
+                    __first + __i, __first + __i + __len, __result + __initial, __mask + __i,
+                    [](_ForwardIterator __x, _Tp* __z)
+                    {
+                        __internal::__invoke_if_else(
+                            std::is_trivial<_Tp>(), [&]() { *__z = std::move(*__x); },
+                            [&]() { ::new (std::addressof(*__z)) _Tp(std::move(*__x)); });
+                    },
+                    _IsVector{});
+            },
+            [&__m](_DifferenceType __total) { __m = __total; });
+
+        // 3. Elements from result are moved to [first, last)
+        __par_backend::__parallel_for(
+            __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __result, __result + __m,
+            [__result, __first](_Tp* __i, _Tp* __j)
+            {
+                __invoke_if_else(
+                    std::is_trivial<_Tp>(), [&]() { __brick_move(__i, __j, __first + (__i - __result), _IsVector{}); },
+                    [&]() { __brick_move_destroy()(__i, __j, __first + (__i - __result), _IsVector{}); });
+            });
+        return __first + __m;
+    });
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _BinaryPredicate>
+_RandomAccessIterator
+__pattern_unique(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                 _RandomAccessIterator __last, _BinaryPredicate __pred) noexcept
+{
+    typedef typename std::iterator_traits<_RandomAccessIterator>::reference _ReferenceType;
+
+    if (__first == __last)
+    {
+        return __last;
+    }
+    if (__first + 1 == __last || __first + 2 == __last)
+    {
+        // Trivial sequence - use serial algorithm
+        return __internal::__brick_unique(__first, __last, __pred, _IsVector{});
+    }
+    return __internal::__remove_elements(
+        __tag, std::forward<_ExecutionPolicy>(__exec), ++__first, __last,
+        [&__pred](bool* __b, bool* __e, _RandomAccessIterator __it)
+        {
+            __internal::__brick_walk3(
+                __b, __e, __it - 1, __it,
+                [&__pred](bool& __x, _ReferenceType __y, _ReferenceType __z) { __x = !__pred(__y, __z); }, _IsVector{});
+        });
+}
+
+//------------------------------------------------------------------------
+// unique_copy
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class OutputIterator, class _BinaryPredicate>
+OutputIterator
+__brick_unique_copy(_ForwardIterator __first, _ForwardIterator __last, OutputIterator __result, _BinaryPredicate __pred,
+                    /*vector=*/std::false_type) noexcept
+{
+    return std::unique_copy(__first, __last, __result, __pred);
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _BinaryPredicate>
+_RandomAccessIterator2
+__brick_unique_copy(_RandomAccessIterator1 __first, _RandomAccessIterator1 __last, _RandomAccessIterator2 __result,
+                    _BinaryPredicate __pred, /*vector=*/std::true_type) noexcept
+{
+#if defined(_PSTL_MONOTONIC_PRESENT)
+    return __unseq_backend::__simd_unique_copy(__first, __last - __first, __result, __pred);
+#else
+    return std::unique_copy(__first, __last, __result, __pred);
+#endif
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _OutputIterator, class _BinaryPredicate>
+_OutputIterator
+__pattern_unique_copy(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last,
+                      _OutputIterator __result, _BinaryPredicate __pred) noexcept
+{
+    return __internal::__brick_unique_copy(__first, __last, __result, __pred, typename _Tag::__is_vector{});
+}
+
+template <class _DifferenceType, class _RandomAccessIterator, class _BinaryPredicate>
+_DifferenceType
+__brick_calc_mask_2(_RandomAccessIterator __first, _RandomAccessIterator __last, bool* __restrict __mask,
+                    _BinaryPredicate __pred, /*vector=*/std::false_type) noexcept
+{
+    _DifferenceType __count = 0;
+    for (; __first != __last; ++__first, ++__mask)
+    {
+        *__mask = !__pred(*__first, *(__first - 1));
+        __count += *__mask;
+    }
+    return __count;
+}
+
+template <class _DifferenceType, class _RandomAccessIterator, class _BinaryPredicate>
+_DifferenceType
+__brick_calc_mask_2(_RandomAccessIterator __first, _RandomAccessIterator __last, bool* __restrict __mask,
+                    _BinaryPredicate __pred, /*vector=*/std::true_type) noexcept
+{
+    return __unseq_backend::__simd_calc_mask_2(__first, __last - __first, __mask, __pred);
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _BinaryPredicate>
+_RandomAccessIterator2
+__pattern_unique_copy(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first,
+                      _RandomAccessIterator1 __last, _RandomAccessIterator2 __result, _BinaryPredicate __pred)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    typedef typename std::iterator_traits<_RandomAccessIterator1>::difference_type _DifferenceType;
+    const _DifferenceType __n = __last - __first;
+    if (_DifferenceType(2) < __n)
+    {
+        __par_backend::__buffer<bool> __mask_buf(__n);
+        if (_DifferenceType(2) < __n)
+        {
+            return __internal::__except_handler(
+                [&__exec, __n, __first, __result, __pred, &__mask_buf]()
+                {
+                    bool* __mask = __mask_buf.get();
+                    _DifferenceType __m{};
+                    __par_backend::__parallel_strict_scan(
+                        __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __n, _DifferenceType(0),
+                        [=](_DifferenceType __i, _DifferenceType __len) -> _DifferenceType { // Reduce
+                            _DifferenceType __extra = 0;
+                            if (__i == 0)
+                            {
+                                // Special boundary case
+                                __mask[__i] = true;
+                                if (--__len == 0)
+                                    return 1;
+                                ++__i;
+                                ++__extra;
+                            }
+                            return __internal::__brick_calc_mask_2<_DifferenceType>(
+                                       __first + __i, __first + (__i + __len), __mask + __i, __pred, _IsVector{}) +
+                                   __extra;
+                        },
+                        std::plus<_DifferenceType>(),                                                // Combine
+                        [=](_DifferenceType __i, _DifferenceType __len, _DifferenceType __initial) { // Scan
+                            // Phase 2 is same as for __pattern_copy_if
+                            __internal::__brick_copy_by_mask(
+                                __first + __i, __first + (__i + __len), __result + __initial, __mask + __i,
+                                [](_RandomAccessIterator1 __x, _RandomAccessIterator2 __z) { *__z = *__x; },
+                                _IsVector{});
+                        },
+                        [&__m](_DifferenceType __total) { __m = __total; });
+                    return __result + __m;
+                });
+        }
+    }
+    // trivial sequence - use serial algorithm
+    return __internal::__brick_unique_copy(__first, __last, __result, __pred, _IsVector{});
+}
+
+//------------------------------------------------------------------------
+// reverse
+//------------------------------------------------------------------------
+template <class _BidirectionalIterator>
+void
+__brick_reverse(_BidirectionalIterator __first, _BidirectionalIterator __last, /*__is_vector=*/std::false_type) noexcept
+{
+    std::reverse(__first, __last);
+}
+
+template <class _RandomAccessIterator>
+void
+__brick_reverse(_RandomAccessIterator __first, _RandomAccessIterator __last, /*__is_vector=*/std::true_type) noexcept
+{
+    typedef typename std::iterator_traits<_RandomAccessIterator>::reference _ReferenceType;
+
+    const auto __n = (__last - __first) / 2;
+    __unseq_backend::__simd_walk_2(__first, __n, std::reverse_iterator<_RandomAccessIterator>(__last),
+                                   [](_ReferenceType __x, _ReferenceType __y) {
+                                       using std::swap;
+                                       swap(__x, __y);
+                                   });
+}
+
+// this brick is called in parallel version, so we can use iterator arithmetic
+template <class _BidirectionalIterator>
+void
+__brick_reverse(_BidirectionalIterator __first, _BidirectionalIterator __last, _BidirectionalIterator __d_last,
+                /*is_vector=*/std::false_type) noexcept
+{
+    for (--__d_last; __first != __last; ++__first, --__d_last)
+    {
+        using std::iter_swap;
+        iter_swap(__first, __d_last);
+    }
+}
+
+// this brick is called in parallel version, so we can use iterator arithmetic
+template <class _RandomAccessIterator>
+void
+__brick_reverse(_RandomAccessIterator __first, _RandomAccessIterator __last, _RandomAccessIterator __d_last,
+                /*is_vector=*/std::true_type) noexcept
+{
+    typedef typename std::iterator_traits<_RandomAccessIterator>::reference _ReferenceType;
+
+    __unseq_backend::__simd_walk_2(__first, __last - __first, std::reverse_iterator<_RandomAccessIterator>(__d_last),
+                                   [](_ReferenceType __x, _ReferenceType __y) {
+                                       using std::swap;
+                                       swap(__x, __y);
+                                   });
+}
+
+template <class _Tag, class _ExecutionPolicy, class _BidirectionalIterator>
+void
+__pattern_reverse(_Tag, _ExecutionPolicy&&, _BidirectionalIterator __first, _BidirectionalIterator __last) noexcept
+{
+    __internal::__brick_reverse(__first, __last, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator>
+void
+__pattern_reverse(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                  _RandomAccessIterator __last)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    __par_backend::__parallel_for(
+        __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __first + (__last - __first) / 2,
+        [__first, __last](_RandomAccessIterator __inner_first, _RandomAccessIterator __inner_last)
+        { __internal::__brick_reverse(__inner_first, __inner_last, __last - (__inner_first - __first), _IsVector{}); });
+}
+
+//------------------------------------------------------------------------
+// reverse_copy
+//------------------------------------------------------------------------
+
+template <class _BidirectionalIterator, class _OutputIterator>
+_OutputIterator
+__brick_reverse_copy(_BidirectionalIterator __first, _BidirectionalIterator __last, _OutputIterator __d_first,
+                     /*is_vector=*/std::false_type) noexcept
+{
+    return std::reverse_copy(__first, __last, __d_first);
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2>
+_RandomAccessIterator2
+__brick_reverse_copy(_RandomAccessIterator1 __first, _RandomAccessIterator1 __last, _RandomAccessIterator2 __d_first,
+                     /*is_vector=*/std::true_type) noexcept
+{
+    typedef typename std::iterator_traits<_RandomAccessIterator1>::reference _ReferenceType1;
+    typedef typename std::iterator_traits<_RandomAccessIterator2>::reference _ReferenceType2;
+
+    return __unseq_backend::__simd_walk_2(std::reverse_iterator<_RandomAccessIterator1>(__last), __last - __first,
+                                          __d_first, [](_ReferenceType1 __x, _ReferenceType2 __y) { __y = __x; });
+}
+
+template <class _Tag, class _ExecutionPolicy, class _BidirectionalIterator, class _OutputIterator>
+_OutputIterator
+__pattern_reverse_copy(_Tag, _ExecutionPolicy&&, _BidirectionalIterator __first, _BidirectionalIterator __last,
+                       _OutputIterator __d_first) noexcept
+{
+    return __internal::__brick_reverse_copy(__first, __last, __d_first, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2>
+_RandomAccessIterator2
+__pattern_reverse_copy(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first,
+                       _RandomAccessIterator1 __last, _RandomAccessIterator2 __d_first)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    auto __len = __last - __first;
+    __par_backend::__parallel_for(
+        __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+        [__first, __len, __d_first](_RandomAccessIterator1 __inner_first, _RandomAccessIterator1 __inner_last)
+        {
+            __internal::__brick_reverse_copy(__inner_first, __inner_last,
+                                             __d_first + (__len - (__inner_last - __first)), _IsVector{});
+        });
+    return __d_first + __len;
+}
+
+//------------------------------------------------------------------------
+// rotate
+//------------------------------------------------------------------------
+template <class _ForwardIterator>
+_ForwardIterator
+__brick_rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last,
+               /*is_vector=*/std::false_type) noexcept
+{
+#if defined(_PSTL_CPP11_STD_ROTATE_BROKEN)
+    std::rotate(__first, __middle, __last);
+    return std::next(__first, std::distance(__middle, __last));
+#else
+    return std::rotate(__first, __middle, __last);
+#endif
+}
+
+template <class _RandomAccessIterator>
+_RandomAccessIterator
+__brick_rotate(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
+               /*is_vector=*/std::true_type) noexcept
+{
+    auto __n = __last - __first;
+    auto __m = __middle - __first;
+    const _RandomAccessIterator __ret = __first + (__last - __middle);
+
+    bool __is_left = (__m <= __n / 2);
+    if (!__is_left)
+        __m = __n - __m;
+
+    while (__n > 1 && __m > 0)
+    {
+        using std::iter_swap;
+        const auto __m_2 = __m * 2;
+        if (__is_left)
+        {
+            for (; __last - __first >= __m_2; __first += __m)
+            {
+                __unseq_backend::__simd_assign(__first, __m, __first + __m,
+                                               iter_swap<_RandomAccessIterator, _RandomAccessIterator>);
+            }
+        }
+        else
+        {
+            for (; __last - __first >= __m_2; __last -= __m)
+            {
+                __unseq_backend::__simd_assign(__last - __m, __m, __last - __m_2,
+                                               iter_swap<_RandomAccessIterator, _RandomAccessIterator>);
+            }
+        }
+        __is_left = !__is_left;
+        __m = __n % __m;
+        __n = __last - __first;
+    }
+
+    return __ret;
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator>
+_ForwardIterator
+__pattern_rotate(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __middle,
+                 _ForwardIterator __last) noexcept
+{
+    return __internal::__brick_rotate(__first, __middle, __last, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator>
+_RandomAccessIterator
+__pattern_rotate(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                 _RandomAccessIterator __middle, _RandomAccessIterator __last)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    typedef typename std::iterator_traits<_RandomAccessIterator>::value_type _Tp;
+    auto __n = __last - __first;
+    auto __m = __middle - __first;
+    if (__m <= __n / 2)
+    {
+        __par_backend::__buffer<_Tp> __buf(__n - __m);
+        return __internal::__except_handler(
+            [&__exec, __n, __m, __first, __middle, __last, &__buf]()
+            {
+                _Tp* __result = __buf.get();
+                __par_backend::__parallel_for(
+                    __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __middle, __last,
+                    [__middle, __result](_RandomAccessIterator __b, _RandomAccessIterator __e)
+                    { __internal::__brick_uninitialized_move(__b, __e, __result + (__b - __middle), _IsVector{}); });
+
+                __par_backend::__parallel_for(
+                    __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __middle,
+                    [__last, __middle](_RandomAccessIterator __b, _RandomAccessIterator __e)
+                    { __internal::__brick_move(__b, __e, __b + (__last - __middle), _IsVector{}); });
+
+                __par_backend::__parallel_for(
+                    __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __result, __result + (__n - __m),
+                    [__first, __result](_Tp* __b, _Tp* __e)
+                    { __brick_move_destroy()(__b, __e, __first + (__b - __result), _IsVector{}); });
+
+                return __first + (__last - __middle);
+            });
+    }
+    else
+    {
+        __par_backend::__buffer<_Tp> __buf(__m);
+        return __internal::__except_handler(
+            [&__exec, __n, __m, __first, __middle, __last, &__buf]()
+            {
+                _Tp* __result = __buf.get();
+                __par_backend::__parallel_for(
+                    __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __middle,
+                    [__first, __result](_RandomAccessIterator __b, _RandomAccessIterator __e)
+                    { __internal::__brick_uninitialized_move(__b, __e, __result + (__b - __first), _IsVector{}); });
+
+                __par_backend::__parallel_for(
+                    __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __middle, __last,
+                    [__first, __middle](_RandomAccessIterator __b, _RandomAccessIterator __e)
+                    { __internal::__brick_move(__b, __e, __first + (__b - __middle), _IsVector{}); });
+
+                __par_backend::__parallel_for(
+                    __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __result, __result + __m,
+                    [__n, __m, __first, __result](_Tp* __b, _Tp* __e)
+                    { __brick_move_destroy()(__b, __e, __first + ((__n - __m) + (__b - __result)), _IsVector{}); });
+
+                return __first + (__last - __middle);
+            });
+    }
+}
+
+//------------------------------------------------------------------------
+// rotate_copy
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _OutputIterator>
+_OutputIterator
+__brick_rotate_copy(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last,
+                    _OutputIterator __result, /*__is_vector=*/std::false_type) noexcept
+{
+    return std::rotate_copy(__first, __middle, __last, __result);
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2>
+_RandomAccessIterator2
+__brick_rotate_copy(_RandomAccessIterator1 __first, _RandomAccessIterator1 __middle, _RandomAccessIterator1 __last,
+                    _RandomAccessIterator2 __result, /*__is_vector=*/std::true_type) noexcept
+{
+    _RandomAccessIterator2 __res = __internal::__brick_copy(__middle, __last, __result, std::true_type());
+    return __internal::__brick_copy(__first, __middle, __res, std::true_type());
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _OutputIterator>
+_OutputIterator
+__pattern_rotate_copy(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __middle,
+                      _ForwardIterator __last, _OutputIterator __result) noexcept
+{
+    return __internal::__brick_rotate_copy(__first, __middle, __last, __result, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2>
+_RandomAccessIterator2
+__pattern_rotate_copy(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first,
+                      _RandomAccessIterator1 __middle, _RandomAccessIterator1 __last, _RandomAccessIterator2 __result)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    __par_backend::__parallel_for(
+        __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+        [__first, __last, __middle, __result](_RandomAccessIterator1 __b, _RandomAccessIterator1 __e)
+        {
+            if (__b > __middle)
+            {
+                __internal::__brick_copy(__b, __e, __result + (__b - __middle), _IsVector{});
+            }
+            else
+            {
+                _RandomAccessIterator2 __new_result = __result + ((__last - __middle) + (__b - __first));
+                if (__e < __middle)
+                {
+                    __internal::__brick_copy(__b, __e, __new_result, _IsVector{});
+                }
+                else
+                {
+                    __internal::__brick_copy(__b, __middle, __new_result, _IsVector{});
+                    __internal::__brick_copy(__middle, __e, __result, _IsVector{});
+                }
+            }
+        });
+    return __result + (__last - __first);
+}
+
+//------------------------------------------------------------------------
+// is_partitioned
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _UnaryPredicate>
+bool
+__brick_is_partitioned(_ForwardIterator __first, _ForwardIterator __last, _UnaryPredicate __pred,
+                       /*is_vector=*/std::false_type) noexcept
+{
+    return std::is_partitioned(__first, __last, __pred);
+}
+
+template <class _RandomAccessIterator, class _UnaryPredicate>
+bool
+__brick_is_partitioned(_RandomAccessIterator __first, _RandomAccessIterator __last, _UnaryPredicate __pred,
+                       /*is_vector=*/std::true_type) noexcept
+{
+    typedef typename std::iterator_traits<_RandomAccessIterator>::difference_type _SizeType;
+    if (__first == __last)
+    {
+        return true;
+    }
+    else
+    {
+        _RandomAccessIterator __result = __unseq_backend::__simd_first(
+            __first, _SizeType(0), __last - __first,
+            [&__pred](_RandomAccessIterator __it, _SizeType __i) { return !__pred(__it[__i]); });
+        if (__result == __last)
+        {
+            return true;
+        }
+        else
+        {
+            ++__result;
+            return !__unseq_backend::__simd_or(__result, __last - __result, __pred);
+        }
+    }
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _UnaryPredicate>
+bool
+__pattern_is_partitioned(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last,
+                         _UnaryPredicate __pred) noexcept
+{
+    return __internal::__brick_is_partitioned(__first, __last, __pred, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _UnaryPredicate>
+bool
+__pattern_is_partitioned(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                         _RandomAccessIterator __last, _UnaryPredicate __pred)
+{
+    if (__first == __last)
+    {
+        return true;
+    }
+    else
+    {
+        using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+        return __internal::__except_handler([&]() {
+            // State of current range:
+            // broken     - current range is not partitioned by pred
+            // all_true   - all elements in current range satisfy pred
+            // all_false  - all elements in current range don't satisfy pred
+            // true_false - elements satisfy pred are placed before elements that don't satisfy pred
+            enum _ReduceType
+            {
+                __not_init = -1,
+                __broken,
+                __all_true,
+                __all_false,
+                __true_false
+            };
+            _ReduceType __init = __not_init;
+
+            // Array with states that we'll have when state from the left branch is merged with state from the right branch.
+            // State is calculated by formula: new_state = table[left_state * 4 + right_state]
+            _ReduceType __table[] = {__broken,     __broken,     __broken,     __broken, __broken,    __all_true,
+                                     __true_false, __true_false, __broken,     __broken, __all_false, __broken,
+                                     __broken,     __broken,     __true_false, __broken};
+
+            __init = __par_backend::__parallel_reduce(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last, __init,
+                [&__pred, &__table](_RandomAccessIterator __i, _RandomAccessIterator __j,
+                                    _ReduceType __value) -> _ReduceType
+                {
+                    if (__value == __broken)
+                    {
+                        return __broken;
+                    }
+                    _ReduceType __res = __not_init;
+                    // if first element satisfy pred
+                    if (__pred(*__i))
+                    {
+                        // find first element that don't satisfy pred
+                        _RandomAccessIterator __x =
+                            __internal::__brick_find_if(__i + 1, __j, std::not_fn(__pred), _IsVector{});
+                        if (__x != __j)
+                        {
+                            // find first element after "x" that satisfy pred
+                            _RandomAccessIterator __y = __internal::__brick_find_if(__x + 1, __j, __pred, _IsVector{});
+                            // if it was found then range isn't partitioned by pred
+                            if (__y != __j)
+                            {
+                                return __broken;
+                            }
+                            else
+                            {
+                                __res = __true_false;
+                            }
+                        }
+                        else
+                        {
+                            __res = __all_true;
+                        }
+                    }
+                    else
+                    { // if first element doesn't satisfy pred
+                        // then we should find the first element that satisfy pred.
+                        // If we found it then range isn't partitioned by pred
+                        if (__internal::__brick_find_if(__i + 1, __j, __pred, _IsVector{}) != __j)
+                        {
+                            return __broken;
+                        }
+                        else
+                        {
+                            __res = __all_false;
+                        }
+                    }
+                    // if we have value from left range then we should calculate the result
+                    return (__value == -1) ? __res : __table[__value * 4 + __res];
+                },
+
+                [&__table](_ReduceType __val1, _ReduceType __val2) -> _ReduceType
+                {
+                    if (__val1 == __broken || __val2 == __broken)
+                    {
+                        return __broken;
+                    }
+                    // calculate the result for new big range
+                    return __table[__val1 * 4 + __val2];
+                });
+            return __init != __broken;
+        });
+    }
+}
+
+//------------------------------------------------------------------------
+// partition
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _UnaryPredicate>
+_ForwardIterator
+__brick_partition(_ForwardIterator __first, _ForwardIterator __last, _UnaryPredicate __pred,
+                  /*is_vector=*/std::false_type) noexcept
+{
+    return std::partition(__first, __last, __pred);
+}
+
+template <class _RandomAccessIterator, class _UnaryPredicate>
+_RandomAccessIterator
+__brick_partition(_RandomAccessIterator __first, _RandomAccessIterator __last, _UnaryPredicate __pred,
+                  /*is_vector=*/std::true_type) noexcept
+{
+    _PSTL_PRAGMA_MESSAGE("Vectorized algorithm unimplemented, redirected to serial");
+    return std::partition(__first, __last, __pred);
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _UnaryPredicate>
+_ForwardIterator
+__pattern_partition(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last,
+                    _UnaryPredicate __pred) noexcept
+{
+    return __internal::__brick_partition(__first, __last, __pred, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _UnaryPredicate>
+_RandomAccessIterator
+__pattern_partition(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                    _RandomAccessIterator __last, _UnaryPredicate __pred)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    // partitioned range: elements before pivot satisfy pred (true part),
+    //                    elements after pivot don't satisfy pred (false part)
+    struct _PartitionRange
+    {
+        _RandomAccessIterator __begin;
+        _RandomAccessIterator __pivot;
+        _RandomAccessIterator __end;
+    };
+
+    return __internal::__except_handler([&]() {
+        _PartitionRange __init{__last, __last, __last};
+
+        // lambda for merging two partitioned ranges to one partitioned range
+        auto __reductor = [&__exec](_PartitionRange __val1, _PartitionRange __val2) -> _PartitionRange
+        {
+            auto __size1 = __val1.__end - __val1.__pivot;
+            auto __size2 = __val2.__pivot - __val2.__begin;
+            auto __new_begin = __val2.__begin - (__val1.__end - __val1.__begin);
+
+            // if all elements in left range satisfy pred then we can move new pivot to pivot of right range
+            if (__val1.__end == __val1.__pivot)
+            {
+                return {__new_begin, __val2.__pivot, __val2.__end};
+            }
+            // if true part of right range greater than false part of left range
+            // then we should swap the false part of left range and last part of true part of right range
+            else if (__size2 > __size1)
+            {
+                __par_backend::__parallel_for(
+                    __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __val1.__pivot, __val1.__pivot + __size1,
+                    [__val1, __val2, __size1](_RandomAccessIterator __i, _RandomAccessIterator __j) {
+                        __internal::__brick_swap_ranges(__i, __j, (__val2.__pivot - __size1) + (__i - __val1.__pivot),
+                                                        _IsVector{});
+                    });
+                return {__new_begin, __val2.__pivot - __size1, __val2.__end};
+            }
+            // else we should swap the first part of false part of left range and true part of right range
+            else
+            {
+                __par_backend::__parallel_for(
+                    __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __val1.__pivot, __val1.__pivot + __size2,
+                    [__val1, __val2](_RandomAccessIterator __i, _RandomAccessIterator __j) {
+                        __internal::__brick_swap_ranges(__i, __j, __val2.__begin + (__i - __val1.__pivot), _IsVector{});
+                    });
+                return {__new_begin, __val1.__pivot + __size2, __val2.__end};
+            }
+        };
+
+        _PartitionRange __result = __par_backend::__parallel_reduce(
+            __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last, __init,
+            [__pred, __reductor](_RandomAccessIterator __i, _RandomAccessIterator __j,
+                                 _PartitionRange __value) -> _PartitionRange
+            {
+                //1. serial partition
+                _RandomAccessIterator __pivot = __internal::__brick_partition(__i, __j, __pred, _IsVector{});
+
+                // 2. merging of two ranges (left and right respectively)
+                return __reductor(__value, {__i, __pivot, __j});
+            },
+            __reductor);
+        return __result.__pivot;
+    });
+}
+
+//------------------------------------------------------------------------
+// stable_partition
+//------------------------------------------------------------------------
+
+template <class _BidirectionalIterator, class _UnaryPredicate>
+_BidirectionalIterator
+__brick_stable_partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _UnaryPredicate __pred,
+                         /*__is_vector=*/std::false_type) noexcept
+{
+    return std::stable_partition(__first, __last, __pred);
+}
+
+template <class _RandomAccessIterator, class _UnaryPredicate>
+_RandomAccessIterator
+__brick_stable_partition(_RandomAccessIterator __first, _RandomAccessIterator __last, _UnaryPredicate __pred,
+                         /*__is_vector=*/std::true_type) noexcept
+{
+    _PSTL_PRAGMA_MESSAGE("Vectorized algorithm unimplemented, redirected to serial");
+    return std::stable_partition(__first, __last, __pred);
+}
+
+template <class _Tag, class _ExecutionPolicy, class _BidirectionalIterator, class _UnaryPredicate>
+_BidirectionalIterator
+__pattern_stable_partition(_Tag, _ExecutionPolicy&&, _BidirectionalIterator __first, _BidirectionalIterator __last,
+                           _UnaryPredicate __pred) noexcept
+{
+    return __internal::__brick_stable_partition(__first, __last, __pred, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _UnaryPredicate>
+_RandomAccessIterator
+__pattern_stable_partition(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                           _RandomAccessIterator __last, _UnaryPredicate __pred) noexcept
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    // partitioned range: elements before pivot satisfy pred (true part),
+    //                    elements after pivot don't satisfy pred (false part)
+    struct _PartitionRange
+    {
+        _RandomAccessIterator __begin;
+        _RandomAccessIterator __pivot;
+        _RandomAccessIterator __end;
+    };
+
+    return __internal::__except_handler([&]() {
+        _PartitionRange __init{__last, __last, __last};
+
+        // lambda for merging two partitioned ranges to one partitioned range
+        auto __reductor = [](_PartitionRange __val1, _PartitionRange __val2) -> _PartitionRange
+        {
+            auto __size1 = __val1.__end - __val1.__pivot;
+            auto __new_begin = __val2.__begin - (__val1.__end - __val1.__begin);
+
+            // if all elements in left range satisfy pred then we can move new pivot to pivot of right range
+            if (__val1.__end == __val1.__pivot)
+            {
+                return {__new_begin, __val2.__pivot, __val2.__end};
+            }
+            // if true part of right range greater than false part of left range
+            // then we should swap the false part of left range and last part of true part of right range
+            else
+            {
+                __internal::__brick_rotate(__val1.__pivot, __val2.__begin, __val2.__pivot, _IsVector{});
+                return {__new_begin, __val2.__pivot - __size1, __val2.__end};
+            }
+        };
+
+        _PartitionRange __result = __par_backend::__parallel_reduce(
+            __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last, __init,
+            [&__pred, __reductor](_RandomAccessIterator __i, _RandomAccessIterator __j,
+                                  _PartitionRange __value) -> _PartitionRange
+            {
+                //1. serial stable_partition
+                _RandomAccessIterator __pivot = __internal::__brick_stable_partition(__i, __j, __pred, _IsVector{});
+
+                // 2. merging of two ranges (left and right respectively)
+                return __reductor(__value, {__i, __pivot, __j});
+            },
+            __reductor);
+        return __result.__pivot;
+    });
+}
+
+//------------------------------------------------------------------------
+// partition_copy
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _OutputIterator1, class _OutputIterator2, class _UnaryPredicate>
+std::pair<_OutputIterator1, _OutputIterator2>
+__brick_partition_copy(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator1 __out_true,
+                       _OutputIterator2 __out_false, _UnaryPredicate __pred, /*is_vector=*/std::false_type) noexcept
+{
+    return std::partition_copy(__first, __last, __out_true, __out_false, __pred);
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _RandomAccessIterator3,
+          class _UnaryPredicate>
+std::pair<_RandomAccessIterator2, _RandomAccessIterator3>
+__brick_partition_copy(_RandomAccessIterator1 __first, _RandomAccessIterator1 __last, _RandomAccessIterator2 __out_true,
+                       _RandomAccessIterator3 __out_false, _UnaryPredicate __pred,
+                       /*is_vector=*/std::true_type) noexcept
+{
+#if defined(_PSTL_MONOTONIC_PRESENT)
+    return __unseq_backend::__simd_partition_copy(__first, __last - __first, __out_true, __out_false, __pred);
+#else
+    return std::partition_copy(__first, __last, __out_true, __out_false, __pred);
+#endif
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _OutputIterator1, class _OutputIterator2,
+          class _UnaryPredicate>
+std::pair<_OutputIterator1, _OutputIterator2>
+__pattern_partition_copy(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last,
+                         _OutputIterator1 __out_true, _OutputIterator2 __out_false, _UnaryPredicate __pred) noexcept
+{
+    return __internal::__brick_partition_copy(__first, __last, __out_true, __out_false, __pred,
+                                              typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _RandomAccessIterator3, class _UnaryPredicate>
+std::pair<_RandomAccessIterator2, _RandomAccessIterator3>
+__pattern_partition_copy(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first,
+                         _RandomAccessIterator1 __last, _RandomAccessIterator2 __out_true,
+                         _RandomAccessIterator3 __out_false, _UnaryPredicate __pred)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    typedef typename std::iterator_traits<_RandomAccessIterator1>::difference_type _DifferenceType;
+    typedef std::pair<_DifferenceType, _DifferenceType> _ReturnType;
+    const _DifferenceType __n = __last - __first;
+    if (_DifferenceType(1) < __n)
+    {
+        __par_backend::__buffer<bool> __mask_buf(__n);
+        return __internal::__except_handler(
+            [&__exec, __n, __first, __out_true, __out_false, __pred, &__mask_buf]()
+            {
+                bool* __mask = __mask_buf.get();
+                _ReturnType __m{};
+                __par_backend::__parallel_strict_scan(
+                    __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __n,
+                    std::make_pair(_DifferenceType(0), _DifferenceType(0)),
+                    [=](_DifferenceType __i, _DifferenceType __len) { // Reduce
+                        return __internal::__brick_calc_mask_1<_DifferenceType>(__first + __i, __first + (__i + __len),
+                                                                                __mask + __i, __pred, _IsVector{});
+                    },
+                    [](const _ReturnType& __x, const _ReturnType& __y) -> _ReturnType
+                    { return std::make_pair(__x.first + __y.first, __x.second + __y.second); }, // Combine
+                    [=](_DifferenceType __i, _DifferenceType __len, _ReturnType __initial) {    // Scan
+                        __internal::__brick_partition_by_mask(
+                            __first + __i, __first + (__i + __len), __out_true + __initial.first,
+                            __out_false + __initial.second, __mask + __i, _IsVector{});
+                    },
+                    [&__m](_ReturnType __total) { __m = __total; });
+                return std::make_pair(__out_true + __m.first, __out_false + __m.second);
+            });
+    }
+    // trivial sequence - use serial algorithm
+    return __internal::__brick_partition_copy(__first, __last, __out_true, __out_false, __pred, _IsVector{});
+}
+
+//------------------------------------------------------------------------
+// sort
+//------------------------------------------------------------------------
+
+template <class _Tag, class _ExecutionPolicy, class _RandomAccessIterator, class _Compare, class _IsMoveConstructible>
+void
+__pattern_sort(_Tag, _ExecutionPolicy&&, _RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
+               _IsMoveConstructible) noexcept
+{
+    std::sort(__first, __last, __comp);
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+void
+__pattern_sort(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+               _RandomAccessIterator __last, _Compare __comp, /*is_move_constructible=*/std::true_type)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    __internal::__except_handler(
+        [&]()
+        {
+            __par_backend::__parallel_stable_sort(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last, __comp,
+                [](_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+                { std::sort(__first, __last, __comp); });
+        });
+}
+
+//------------------------------------------------------------------------
+// stable_sort
+//------------------------------------------------------------------------
+
+template <class _Tag, class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+void
+__pattern_stable_sort(_Tag, _ExecutionPolicy&&, _RandomAccessIterator __first, _RandomAccessIterator __last,
+                      _Compare __comp) noexcept
+{
+    std::stable_sort(__first, __last, __comp);
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+void
+__pattern_stable_sort(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                      _RandomAccessIterator __last, _Compare __comp)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    __internal::__except_handler(
+        [&]()
+        {
+            __par_backend::__parallel_stable_sort(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last, __comp,
+                [](_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+                { std::stable_sort(__first, __last, __comp); });
+        });
+}
+
+//------------------------------------------------------------------------
+// partial_sort
+//------------------------------------------------------------------------
+
+template <class _Tag, class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+void
+__pattern_partial_sort(_Tag, _ExecutionPolicy&&, _RandomAccessIterator __first, _RandomAccessIterator __middle,
+                       _RandomAccessIterator __last, _Compare __comp) noexcept
+{
+    std::partial_sort(__first, __middle, __last, __comp);
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+void
+__pattern_partial_sort(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                       _RandomAccessIterator __middle, _RandomAccessIterator __last, _Compare __comp)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    const auto __n = __middle - __first;
+    if (__n == 0)
+        return;
+
+    __internal::__except_handler(
+        [&]()
+        {
+            __par_backend::__parallel_stable_sort(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last, __comp,
+                [__n](_RandomAccessIterator __begin, _RandomAccessIterator __end, _Compare __comp)
+                {
+                    if (__n < __end - __begin)
+                        std::partial_sort(__begin, __begin + __n, __end, __comp);
+                    else
+                        std::sort(__begin, __end, __comp);
+                },
+                __n);
+        });
+}
+
+//------------------------------------------------------------------------
+// partial_sort_copy
+//------------------------------------------------------------------------
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _RandomAccessIterator, class _Compare>
+_RandomAccessIterator
+__pattern_partial_sort_copy(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last,
+                            _RandomAccessIterator __d_first, _RandomAccessIterator __d_last, _Compare __comp) noexcept
+{
+    return std::partial_sort_copy(__first, __last, __d_first, __d_last, __comp);
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _Compare>
+_RandomAccessIterator2
+__pattern_partial_sort_copy(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first,
+                            _RandomAccessIterator1 __last, _RandomAccessIterator2 __d_first,
+                            _RandomAccessIterator2 __d_last, _Compare __comp)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    if (__last == __first || __d_last == __d_first)
+    {
+        return __d_first;
+    }
+    auto __n1 = __last - __first;
+    auto __n2 = __d_last - __d_first;
+    return __internal::__except_handler([&]() {
+        if (__n2 >= __n1)
+        {
+            __par_backend::__parallel_stable_sort(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __d_first, __d_first + __n1, __comp,
+                [__first, __d_first](_RandomAccessIterator2 __i, _RandomAccessIterator2 __j, _Compare __comp)
+                {
+                    _RandomAccessIterator1 __i1 = __first + (__i - __d_first);
+                    _RandomAccessIterator1 __j1 = __first + (__j - __d_first);
+
+                // 1. Copy elements from input to output
+#if !defined(_PSTL_ICC_18_OMP_SIMD_BROKEN)
+                    __internal::__brick_copy(__i1, __j1, __i, _IsVector{});
+#else
+                    std::copy(__i1, __j1, __i);
+#endif
+                    // 2. Sort elements in output sequence
+                    std::sort(__i, __j, __comp);
+                },
+                __n1);
+            return __d_first + __n1;
+        }
+        else
+        {
+            typedef typename std::iterator_traits<_RandomAccessIterator1>::value_type _T1;
+            typedef typename std::iterator_traits<_RandomAccessIterator2>::value_type _T2;
+            __par_backend::__buffer<_T1> __buf(__n1);
+            _T1* __r = __buf.get();
+
+            __par_backend::__parallel_stable_sort(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __r, __r + __n1, __comp,
+                [__n2, __first, __r](_T1* __i, _T1* __j, _Compare __comp)
+                {
+                    _RandomAccessIterator1 __it = __first + (__i - __r);
+
+                    // 1. Copy elements from input to raw memory
+                    for (_T1* __k = __i; __k != __j; ++__k, ++__it)
+                    {
+                        ::new (__k) _T2(*__it);
+                    }
+
+                    // 2. Sort elements in temporary __buffer
+                    if (__n2 < __j - __i)
+                        std::partial_sort(__i, __i + __n2, __j, __comp);
+                    else
+                        std::sort(__i, __j, __comp);
+                },
+                __n2);
+
+            // 3. Move elements from temporary __buffer to output
+            __par_backend::__parallel_for(__backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __r, __r + __n2,
+                                          [__r, __d_first](_T1* __i, _T1* __j)
+                                          { __brick_move_destroy()(__i, __j, __d_first + (__i - __r), _IsVector{}); });
+            __par_backend::__parallel_for(__backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __r + __n2,
+                                          __r + __n1,
+                                          [](_T1* __i, _T1* __j) { __brick_destroy(__i, __j, _IsVector{}); });
+
+            return __d_first + __n2;
+        }
+    });
+}
+
+//------------------------------------------------------------------------
+// adjacent_find
+//------------------------------------------------------------------------
+template <class _RandomAccessIterator, class _BinaryPredicate>
+_RandomAccessIterator
+__brick_adjacent_find(_RandomAccessIterator __first, _RandomAccessIterator __last, _BinaryPredicate __pred,
+                      /* IsVector = */ std::true_type, bool __or_semantic) noexcept
+{
+    return __unseq_backend::__simd_adjacent_find(__first, __last, __pred, __or_semantic);
+}
+
+template <class _ForwardIterator, class _BinaryPredicate>
+_ForwardIterator
+__brick_adjacent_find(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred,
+                      /* IsVector = */ std::false_type, bool) noexcept
+{
+    return std::adjacent_find(__first, __last, __pred);
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _BinaryPredicate>
+_ForwardIterator
+__pattern_adjacent_find(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last,
+                        _BinaryPredicate __pred, bool __or_semantic) noexcept
+{
+    return __internal::__brick_adjacent_find(__first, __last, __pred, typename _Tag::__is_vector{}, __or_semantic);
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _BinaryPredicate>
+_RandomAccessIterator
+__pattern_adjacent_find(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                        _RandomAccessIterator __last, _BinaryPredicate __pred, bool __or_semantic)
+{
+    if (__last - __first < 2)
+        return __last;
+
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    return __internal::__except_handler(
+        [&]()
+        {
+            return __par_backend::__parallel_reduce(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last, __last,
+                [__last, __pred, __or_semantic](_RandomAccessIterator __begin, _RandomAccessIterator __end,
+                                                _RandomAccessIterator __value) -> _RandomAccessIterator
+                {
+                    // TODO: investigate performance benefits from the use of shared variable for the result,
+                    // checking (compare_and_swap idiom) its __value at __first.
+                    if (__or_semantic && __value < __last)
+                    { //found
+                        __par_backend::__cancel_execution();
+                        return __value;
+                    }
+
+                    if (__value > __begin)
+                    {
+                        // modify __end to check the predicate on the boundary __values;
+                        // TODO: to use a custom range with boundaries overlapping
+                        // TODO: investigate what if we remove "if" below and run algorithm on range [__first, __last-1)
+                        // then check the pair [__last-1, __last)
+                        if (__end != __last)
+                            ++__end;
+
+                        //correct the global result iterator if the "brick" returns a local "__last"
+                        const _RandomAccessIterator __res =
+                            __internal::__brick_adjacent_find(__begin, __end, __pred, _IsVector{}, __or_semantic);
+                        if (__res < __end)
+                            __value = __res;
+                    }
+                    return __value;
+                },
+                [](_RandomAccessIterator __x, _RandomAccessIterator __y) -> _RandomAccessIterator
+                { return __x < __y ? __x : __y; } //reduce a __value
+            );
+        });
+}
+
+//------------------------------------------------------------------------
+// nth_element
+//------------------------------------------------------------------------
+
+template <class _Tag, class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+void
+__pattern_nth_element(_Tag, _ExecutionPolicy&&, _RandomAccessIterator __first, _RandomAccessIterator __nth,
+                      _RandomAccessIterator __last, _Compare __comp) noexcept
+{
+    std::nth_element(__first, __nth, __last, __comp);
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+void
+__pattern_nth_element(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                      _RandomAccessIterator __nth, _RandomAccessIterator __last, _Compare __comp) noexcept
+{
+    if (__first == __last || __nth == __last)
+    {
+        return;
+    }
+
+    using std::iter_swap;
+    typedef typename std::iterator_traits<_RandomAccessIterator>::value_type _Tp;
+    _RandomAccessIterator __x;
+    do
+    {
+        __x = __internal::__pattern_partition(__tag, std::forward<_ExecutionPolicy>(__exec), __first + 1, __last,
+                                              [&__comp, __first](const _Tp& __x) { return __comp(__x, *__first); });
+        --__x;
+        if (__x != __first)
+        {
+            iter_swap(__first, __x);
+        }
+        // if x > nth then our new range for partition is [first, x)
+        if (__x - __nth > 0)
+        {
+            __last = __x;
+        }
+        // if x < nth then our new range for partition is [x, last)
+        else if (__x - __nth < 0)
+        {
+            // if *x == *nth then we can start new partition with x+1
+            if (!__comp(*__nth, *__x) && !__comp(*__x, *__nth))
+            {
+                ++__x;
+            }
+            else
+            {
+                iter_swap(__nth, __x);
+            }
+            __first = __x;
+        }
+    } while (__x != __nth);
+}
+
+//------------------------------------------------------------------------
+// fill, fill_n
+//------------------------------------------------------------------------
+template <class _RandomAccessIterator, class _Tp>
+void
+__brick_fill(_RandomAccessIterator __first, _RandomAccessIterator __last, const _Tp& __value,
+             /* __is_vector = */ std::true_type) noexcept
+{
+    __unseq_backend::__simd_fill_n(__first, __last - __first, __value);
+}
+
+template <class _ForwardIterator, class _Tp>
+void
+__brick_fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value,
+             /* __is_vector = */ std::false_type) noexcept
+{
+    std::fill(__first, __last, __value);
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _Tp>
+void
+__pattern_fill(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) noexcept
+{
+    __internal::__brick_fill(__first, __last, __value, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Tp>
+_RandomAccessIterator
+__pattern_fill(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+               _RandomAccessIterator __last, const _Tp& __value)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    return __internal::__except_handler(
+        [&__exec, __first, __last, &__value]()
+        {
+            __par_backend::__parallel_for(__backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                          [&__value](_RandomAccessIterator __begin, _RandomAccessIterator __end)
+                                          { __internal::__brick_fill(__begin, __end, __value, _IsVector{}); });
+            return __last;
+        });
+}
+
+template <class _RandomAccessIterator, class _Size, class _Tp>
+_RandomAccessIterator
+__brick_fill_n(_RandomAccessIterator __first, _Size __count, const _Tp& __value,
+               /* __is_vector = */ std::true_type) noexcept
+{
+    return __unseq_backend::__simd_fill_n(__first, __count, __value);
+}
+
+template <class _OutputIterator, class _Size, class _Tp>
+_OutputIterator
+__brick_fill_n(_OutputIterator __first, _Size __count, const _Tp& __value, /* __is_vector = */ std::false_type) noexcept
+{
+    return std::fill_n(__first, __count, __value);
+}
+
+template <class _Tag, class _ExecutionPolicy, class _OutputIterator, class _Size, class _Tp>
+_OutputIterator
+__pattern_fill_n(_Tag, _ExecutionPolicy&&, _OutputIterator __first, _Size __count, const _Tp& __value) noexcept
+{
+    return __internal::__brick_fill_n(__first, __count, __value, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Size, class _Tp>
+_RandomAccessIterator
+__pattern_fill_n(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                 _Size __count, const _Tp& __value)
+{
+    return __internal::__pattern_fill(__tag, std::forward<_ExecutionPolicy>(__exec), __first, __first + __count,
+                                      __value);
+}
+
+//------------------------------------------------------------------------
+// generate, generate_n
+//------------------------------------------------------------------------
+template <class _RandomAccessIterator, class _Generator>
+void
+__brick_generate(_RandomAccessIterator __first, _RandomAccessIterator __last, _Generator __g,
+                 /* is_vector = */ std::true_type) noexcept
+{
+    __unseq_backend::__simd_generate_n(__first, __last - __first, __g);
+}
+
+template <class _ForwardIterator, class _Generator>
+void
+__brick_generate(_ForwardIterator __first, _ForwardIterator __last, _Generator __g,
+                 /* is_vector = */ std::false_type) noexcept
+{
+    std::generate(__first, __last, __g);
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _Generator>
+void
+__pattern_generate(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last, _Generator __g) noexcept
+{
+    __internal::__brick_generate(__first, __last, __g, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Generator>
+_RandomAccessIterator
+__pattern_generate(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                   _RandomAccessIterator __last, _Generator __g)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    return __internal::__except_handler(
+        [&]()
+        {
+            __par_backend::__parallel_for(__backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                          [__g](_RandomAccessIterator __begin, _RandomAccessIterator __end)
+                                          { __internal::__brick_generate(__begin, __end, __g, _IsVector{}); });
+            return __last;
+        });
+}
+
+template <class _RandomAccessIterator, class Size, class _Generator>
+_RandomAccessIterator
+__brick_generate_n(_RandomAccessIterator __first, Size __count, _Generator __g,
+                   /* is_vector = */ std::true_type) noexcept
+{
+    return __unseq_backend::__simd_generate_n(__first, __count, __g);
+}
+
+template <class OutputIterator, class Size, class _Generator>
+OutputIterator
+__brick_generate_n(OutputIterator __first, Size __count, _Generator __g, /* is_vector = */ std::false_type) noexcept
+{
+    return std::generate_n(__first, __count, __g);
+}
+
+template <class _Tag, class _ExecutionPolicy, class _OutputIterator, class _Size, class _Generator>
+_OutputIterator
+__pattern_generate_n(_Tag, _ExecutionPolicy&&, _OutputIterator __first, _Size __count, _Generator __g) noexcept
+{
+    return __internal::__brick_generate_n(__first, __count, __g, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Size, class _Generator>
+_RandomAccessIterator
+__pattern_generate_n(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                     _Size __count, _Generator __g)
+{
+    static_assert(__are_random_access_iterators<_RandomAccessIterator>::value,
+                  "Pattern-brick error. Should be a random access iterator.");
+    return __internal::__pattern_generate(__tag, std::forward<_ExecutionPolicy>(__exec), __first, __first + __count,
+                                          __g);
+}
+
+//------------------------------------------------------------------------
+// remove
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _UnaryPredicate>
+_ForwardIterator
+__brick_remove_if(_ForwardIterator __first, _ForwardIterator __last, _UnaryPredicate __pred,
+                  /* __is_vector = */ std::false_type) noexcept
+{
+    return std::remove_if(__first, __last, __pred);
+}
+
+template <class _RandomAccessIterator, class _UnaryPredicate>
+_RandomAccessIterator
+__brick_remove_if(_RandomAccessIterator __first, _RandomAccessIterator __last, _UnaryPredicate __pred,
+                  /* __is_vector = */ std::true_type) noexcept
+{
+#if defined(_PSTL_MONOTONIC_PRESENT)
+    return __unseq_backend::__simd_remove_if(__first, __last - __first, __pred);
+#else
+    return std::remove_if(__first, __last, __pred);
+#endif
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _UnaryPredicate>
+_ForwardIterator
+__pattern_remove_if(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last,
+                    _UnaryPredicate __pred) noexcept
+{
+    return __internal::__brick_remove_if(__first, __last, __pred, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _UnaryPredicate>
+_RandomAccessIterator
+__pattern_remove_if(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                    _RandomAccessIterator __last, _UnaryPredicate __pred) noexcept
+{
+    typedef typename std::iterator_traits<_RandomAccessIterator>::reference _ReferenceType;
+
+    if (__first == __last || __first + 1 == __last)
+    {
+        // Trivial sequence - use serial algorithm
+        return __internal::__brick_remove_if(__first, __last, __pred, _IsVector{});
+    }
+
+    return __internal::__remove_elements(
+        __tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+        [&__pred](bool* __b, bool* __e, _RandomAccessIterator __it)
+        {
+            __internal::__brick_walk2(
+                __b, __e, __it, [&__pred](bool& __x, _ReferenceType __y) { __x = !__pred(__y); }, _IsVector{});
+        });
+}
+
+//------------------------------------------------------------------------
+// merge
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _OutputIterator, class _Compare>
+_OutputIterator
+__brick_merge(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+              _ForwardIterator2 __last2, _OutputIterator __d_first, _Compare __comp,
+              /* __is_vector = */ std::false_type) noexcept
+{
+    return std::merge(__first1, __last1, __first2, __last2, __d_first, __comp);
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _RandomAccessIterator3, class _Compare>
+_RandomAccessIterator3
+__brick_merge(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2,
+              _RandomAccessIterator2 __last2, _RandomAccessIterator3 __d_first, _Compare __comp,
+              /* __is_vector = */ std::true_type) noexcept
+{
+    _PSTL_PRAGMA_MESSAGE("Vectorized algorithm unimplemented, redirected to serial");
+    return std::merge(__first1, __last1, __first2, __last2, __d_first, __comp);
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _OutputIterator,
+          class _Compare>
+_OutputIterator
+__pattern_merge(_Tag, _ExecutionPolicy&&, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                _ForwardIterator2 __first2, _ForwardIterator2 __last2, _OutputIterator __d_first,
+                _Compare __comp) noexcept
+{
+    return __internal::__brick_merge(__first1, __last1, __first2, __last2, __d_first, __comp,
+                                     typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _RandomAccessIterator3, class _Compare>
+_RandomAccessIterator3
+__pattern_merge(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first1,
+                _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2,
+                _RandomAccessIterator3 __d_first, _Compare __comp)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    __par_backend::__parallel_merge(
+        __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __first2, __last2, __d_first,
+        __comp,
+        [](_RandomAccessIterator1 __f1, _RandomAccessIterator1 __l1, _RandomAccessIterator2 __f2,
+           _RandomAccessIterator2 __l2, _RandomAccessIterator3 __f3, _Compare __comp)
+        { return __internal::__brick_merge(__f1, __l1, __f2, __l2, __f3, __comp, _IsVector{}); });
+    return __d_first + (__last1 - __first1) + (__last2 - __first2);
+}
+
+//------------------------------------------------------------------------
+// inplace_merge
+//------------------------------------------------------------------------
+template <class _BidirectionalIterator, class _Compare>
+void
+__brick_inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
+                      _Compare __comp, /* __is_vector = */ std::false_type) noexcept
+{
+    std::inplace_merge(__first, __middle, __last, __comp);
+}
+
+template <class _RandomAccessIterator, class _Compare>
+void
+__brick_inplace_merge(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
+                      _Compare __comp, /* __is_vector = */ std::true_type) noexcept
+{
+    _PSTL_PRAGMA_MESSAGE("Vectorized algorithm unimplemented, redirected to serial")
+    std::inplace_merge(__first, __middle, __last, __comp);
+}
+
+template <class _Tag, class _ExecutionPolicy, class _BidirectionalIterator, class _Compare>
+void
+__pattern_inplace_merge(_Tag, _ExecutionPolicy&&, _BidirectionalIterator __first, _BidirectionalIterator __middle,
+                        _BidirectionalIterator __last, _Compare __comp) noexcept
+{
+    __internal::__brick_inplace_merge(__first, __middle, __last, __comp, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+void
+__pattern_inplace_merge(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                        _RandomAccessIterator __middle, _RandomAccessIterator __last, _Compare __comp)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    if (__first == __last || __first == __middle || __middle == __last)
+    {
+        return;
+    }
+    typedef typename std::iterator_traits<_RandomAccessIterator>::value_type _Tp;
+    auto __n = __last - __first;
+    __par_backend::__buffer<_Tp> __buf(__n);
+    _Tp* __r = __buf.get();
+    __internal::__except_handler(
+        [&]()
+        {
+            auto __move_values = [](_RandomAccessIterator __x, _Tp* __z)
+            {
+                __internal::__invoke_if_else(
+                    std::is_trivial<_Tp>(), [&]() { *__z = std::move(*__x); },
+                    [&]() { ::new (std::addressof(*__z)) _Tp(std::move(*__x)); });
+            };
+
+            auto __move_sequences = [](_RandomAccessIterator __first1, _RandomAccessIterator __last1, _Tp* __first2)
+            { return __internal::__brick_uninitialized_move(__first1, __last1, __first2, _IsVector()); };
+
+            __par_backend::__parallel_merge(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __middle, __middle, __last, __r,
+                __comp,
+                [__n, __move_values, __move_sequences](_RandomAccessIterator __f1, _RandomAccessIterator __l1,
+                                                       _RandomAccessIterator __f2, _RandomAccessIterator __l2,
+                                                       _Tp* __f3, _Compare __comp)
+                {
+                    (__utils::__serial_move_merge(__n))(__f1, __l1, __f2, __l2, __f3, __comp, __move_values,
+                                                        __move_values, __move_sequences, __move_sequences);
+                    return __f3 + (__l1 - __f1) + (__l2 - __f2);
+                });
+            __par_backend::__parallel_for(__backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __r, __r + __n,
+                                          [__r, __first](_Tp* __i, _Tp* __j)
+                                          { __brick_move_destroy()(__i, __j, __first + (__i - __r), _IsVector{}); });
+        });
+}
+
+//------------------------------------------------------------------------
+// includes
+//------------------------------------------------------------------------
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Compare>
+bool
+__pattern_includes(_Tag, _ExecutionPolicy&&, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                   _ForwardIterator2 __first2, _ForwardIterator2 __last2, _Compare __comp) noexcept
+{
+    return std::includes(__first1, __last1, __first2, __last2, __comp);
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _Compare>
+bool
+__pattern_includes(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first1,
+                   _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2,
+                   _Compare __comp)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    if (__first2 >= __last2)
+        return true;
+
+    if (__first1 >= __last1 || __comp(*__first2, *__first1) || __comp(*(__last1 - 1), *(__last2 - 1)))
+        return false;
+
+    __first1 = std::lower_bound(__first1, __last1, *__first2, __comp);
+    if (__first1 == __last1)
+        return false;
+
+    if (__last2 - __first2 == 1)
+        return !__comp(*__first1, *__first2) && !__comp(*__first2, *__first1);
+
+    return __internal::__except_handler(
+        [&]()
+        {
+            return !__internal::__parallel_or(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first2, __last2,
+                [__first1, __last1, __first2, __last2, &__comp](_RandomAccessIterator2 __i, _RandomAccessIterator2 __j)
+                {
+                    _PSTL_ASSERT(__j > __i);
+                    //_PSTL_ASSERT(__j - __i > 1);
+
+                    //1. moving boundaries to "consume" subsequence of equal elements
+                    auto __is_equal = [&__comp](_RandomAccessIterator2 __a, _RandomAccessIterator2 __b) -> bool
+                    { return !__comp(*__a, *__b) && !__comp(*__b, *__a); };
+
+                    //1.1 left bound, case "aaa[aaaxyz...]" - searching "x"
+                    if (__i > __first2 && __is_equal(__i, __i - 1))
+                    {
+                        //whole subrange continues to content equal elements - return "no op"
+                        if (__is_equal(__i, __j - 1))
+                            return false;
+
+                        __i = std::upper_bound(__i, __last2, *__i, __comp);
+                    }
+
+                    //1.2 right bound, case "[...aaa]aaaxyz" - searching "x"
+                    if (__j < __last2 && __is_equal(__j - 1, __j))
+                        __j = std::upper_bound(__j, __last2, *__j, __comp);
+
+                    //2. testing is __a subsequence of the second range included into the first range
+                    auto __b = std::lower_bound(__first1, __last1, *__i, __comp);
+
+                    _PSTL_ASSERT(!__comp(*(__last1 - 1), *__b));
+                    _PSTL_ASSERT(!__comp(*(__j - 1), *__i));
+                    return !std::includes(__b, __last1, __i, __j, __comp);
+                });
+        });
+}
+
+constexpr auto __set_algo_cut_off = 1000;
+
+template <class _IsVector, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2,
+          class _OutputIterator, class _Compare, class _SizeFunction, class _SetOP>
+_OutputIterator
+__parallel_set_op(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _ForwardIterator1 __first1,
+                  _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2,
+                  _OutputIterator __result, _Compare __comp, _SizeFunction __size_func, _SetOP __set_op)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    typedef typename std::iterator_traits<_ForwardIterator1>::difference_type _DifferenceType;
+    typedef typename std::iterator_traits<_OutputIterator>::value_type _Tp;
+
+    struct _SetRange
+    {
+        _DifferenceType __pos, __len, __buf_pos;
+        bool
+        empty() const
+        {
+            return __len == 0;
+        }
+    };
+
+    const _DifferenceType __n1 = __last1 - __first1;
+    const _DifferenceType __n2 = __last2 - __first2;
+
+    __par_backend::__buffer<_Tp> __buf(__size_func(__n1, __n2));
+
+    return __internal::__except_handler(
+        [&__exec, __n1, __first1, __last1, __first2, __last2, __result, __comp, __size_func, __set_op, &__buf]()
+        {
+            auto __buffer = __buf.get();
+            _DifferenceType __m{};
+            auto __scan = [=](_DifferenceType, _DifferenceType, const _SetRange& __s) { // Scan
+                if (!__s.empty())
+                    __brick_move_destroy()(__buffer + __s.__buf_pos, __buffer + (__s.__buf_pos + __s.__len),
+                                           __result + __s.__pos, _IsVector{});
+            };
+            __par_backend::__parallel_strict_scan(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __n1, _SetRange{0, 0, 0}, //-1, 0},
+                [=](_DifferenceType __i, _DifferenceType __len) {                                  // Reduce
+                    //[__b; __e) - a subrange of the first sequence, to reduce
+                    _ForwardIterator1 __b = __first1 + __i, __e = __first1 + (__i + __len);
+
+                    //try searching for the first element which not equal to *__b
+                    if (__b != __first1)
+                        __b = std::upper_bound(__b, __last1, *__b, __comp);
+
+                    //try searching for the first element which not equal to *__e
+                    if (__e != __last1)
+                        __e = std::upper_bound(__e, __last1, *__e, __comp);
+
+                    //check is [__b; __e) empty
+                    if (__e - __b < 1)
+                    {
+                        _ForwardIterator2 __bb = __last2;
+                        if (__b != __last1)
+                            __bb = std::lower_bound(__first2, __last2, *__b, __comp);
+
+                        const _DifferenceType __buf_pos = __size_func((__b - __first1), (__bb - __first2));
+                        return _SetRange{0, 0, __buf_pos};
+                    }
+
+                    //try searching for "corresponding" subrange [__bb; __ee) in the second sequence
+                    _ForwardIterator2 __bb = __first2;
+                    if (__b != __first1)
+                        __bb = std::lower_bound(__first2, __last2, *__b, __comp);
+
+                    _ForwardIterator2 __ee = __last2;
+                    if (__e != __last1)
+                        __ee = std::lower_bound(__bb, __last2, *__e, __comp);
+
+                    const _DifferenceType __buf_pos = __size_func((__b - __first1), (__bb - __first2));
+                    auto __buffer_b = __buffer + __buf_pos;
+                    auto __res = __set_op(__b, __e, __bb, __ee, __buffer_b, __comp);
+
+                    return _SetRange{0, __res - __buffer_b, __buf_pos};
+                },
+                [](const _SetRange& __a, const _SetRange& __b) { // Combine
+                    if (__b.__buf_pos > __a.__buf_pos || ((__b.__buf_pos == __a.__buf_pos) && !__b.empty()))
+                        return _SetRange{__a.__pos + __a.__len + __b.__pos, __b.__len, __b.__buf_pos};
+                    return _SetRange{__b.__pos + __b.__len + __a.__pos, __a.__len, __a.__buf_pos};
+                },
+                __scan,                                     // Scan
+                [&__m, &__scan](const _SetRange& __total) { // Apex
+                    //final scan
+                    __scan(0, 0, __total);
+                    __m = __total.__pos + __total.__len;
+                });
+            return __result + __m;
+        });
+}
+
+//a shared parallel pattern for '__pattern_set_union' and '__pattern_set_symmetric_difference'
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _OutputIterator,
+          class _Compare, class _SetUnionOp>
+_OutputIterator
+__parallel_set_union_op(_Tag __tag, _ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                        _ForwardIterator2 __first2, _ForwardIterator2 __last2, _OutputIterator __result,
+                        _Compare __comp, _SetUnionOp __set_union_op)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    typedef typename std::iterator_traits<_ForwardIterator1>::difference_type _DifferenceType;
+
+    const auto __n1 = __last1 - __first1;
+    const auto __n2 = __last2 - __first2;
+
+    auto copy_range1 = [](_ForwardIterator1 __begin, _ForwardIterator1 __end, _OutputIterator __res)
+    { return __internal::__brick_copy(__begin, __end, __res, typename _Tag::__is_vector{}); };
+    auto copy_range2 = [](_ForwardIterator2 __begin, _ForwardIterator2 __end, _OutputIterator __res)
+    { return __internal::__brick_copy(__begin, __end, __res, typename _Tag::__is_vector{}); };
+
+    // {1} {}: parallel copying just first sequence
+    if (__n2 == 0)
+        return __internal::__pattern_walk2_brick(__tag, std::forward<_ExecutionPolicy>(__exec), __first1, __last1,
+                                                 __result, copy_range1);
+
+    // {} {2}: parallel copying justmake  second sequence
+    if (__n1 == 0)
+        return __internal::__pattern_walk2_brick(__tag, std::forward<_ExecutionPolicy>(__exec), __first2, __last2,
+                                                 __result, copy_range2);
+
+    // testing  whether the sequences are intersected
+    _ForwardIterator1 __left_bound_seq_1 = std::lower_bound(__first1, __last1, *__first2, __comp);
+
+    if (__left_bound_seq_1 == __last1)
+    {
+        //{1} < {2}: seq2 is wholly greater than seq1, so, do parallel copying seq1 and seq2
+        __par_backend::__parallel_invoke(
+            __backend_tag{}, std::forward<_ExecutionPolicy>(__exec),
+            [=]
+            {
+                __internal::__pattern_walk2_brick(__tag, std::forward<_ExecutionPolicy>(__exec), __first1, __last1,
+                                                  __result, copy_range1);
+            },
+            [=]
+            {
+                __internal::__pattern_walk2_brick(__tag, std::forward<_ExecutionPolicy>(__exec), __first2, __last2,
+                                                  __result + __n1, copy_range2);
+            });
+        return __result + __n1 + __n2;
+    }
+
+    // testing  whether the sequences are intersected
+    _ForwardIterator2 __left_bound_seq_2 = std::lower_bound(__first2, __last2, *__first1, __comp);
+
+    if (__left_bound_seq_2 == __last2)
+    {
+        //{2} < {1}: seq2 is wholly greater than seq1, so, do parallel copying seq1 and seq2
+        __par_backend::__parallel_invoke(
+            __backend_tag{}, std::forward<_ExecutionPolicy>(__exec),
+            [=]
+            {
+                __internal::__pattern_walk2_brick(__tag, std::forward<_ExecutionPolicy>(__exec), __first2, __last2,
+                                                  __result, copy_range2);
+            },
+            [=]
+            {
+                __internal::__pattern_walk2_brick(__tag, std::forward<_ExecutionPolicy>(__exec), __first1, __last1,
+                                                  __result + __n2, copy_range1);
+            });
+        return __result + __n1 + __n2;
+    }
+
+    const auto __m1 = __left_bound_seq_1 - __first1;
+    if (__m1 > __set_algo_cut_off)
+    {
+        auto __res_or = __result;
+        __result += __m1; //we know proper offset due to [first1; left_bound_seq_1) < [first2; last2)
+        __par_backend::__parallel_invoke(
+            __backend_tag{}, std::forward<_ExecutionPolicy>(__exec),
+            //do parallel copying of [first1; left_bound_seq_1)
+            [=]
+            {
+                __internal::__pattern_walk2_brick(__tag, std::forward<_ExecutionPolicy>(__exec), __first1,
+                                                  __left_bound_seq_1, __res_or, copy_range1);
+            },
+            [=, &__result]
+            {
+                __result = __internal::__parallel_set_op(
+                    __tag, std::forward<_ExecutionPolicy>(__exec), __left_bound_seq_1, __last1, __first2, __last2,
+                    __result, __comp, [](_DifferenceType __n, _DifferenceType __m) { return __n + __m; },
+                    __set_union_op);
+            });
+        return __result;
+    }
+
+    const auto __m2 = __left_bound_seq_2 - __first2;
+    _PSTL_ASSERT(__m1 == 0 || __m2 == 0);
+    if (__m2 > __set_algo_cut_off)
+    {
+        auto __res_or = __result;
+        __result += __m2; //we know proper offset due to [first2; left_bound_seq_2) < [first1; last1)
+        __par_backend::__parallel_invoke(
+            __backend_tag{}, std::forward<_ExecutionPolicy>(__exec),
+            //do parallel copying of [first2; left_bound_seq_2)
+            [=]
+            {
+                __internal::__pattern_walk2_brick(__tag, std::forward<_ExecutionPolicy>(__exec), __first2,
+                                                  __left_bound_seq_2, __res_or, copy_range2);
+            },
+            [=, &__result]
+            {
+                __result = __internal::__parallel_set_op(
+                    __tag, std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __left_bound_seq_2, __last2,
+                    __result, __comp, [](_DifferenceType __n, _DifferenceType __m) { return __n + __m; },
+                    __set_union_op);
+            });
+        return __result;
+    }
+
+    return __internal::__parallel_set_op(
+        __tag, std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __first2, __last2, __result, __comp,
+        [](_DifferenceType __n, _DifferenceType __m) { return __n + __m; }, __set_union_op);
+}
+
+//------------------------------------------------------------------------
+// set_union
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _OutputIterator, class _Compare>
+_OutputIterator
+__brick_set_union(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+                  _ForwardIterator2 __last2, _OutputIterator __result, _Compare __comp,
+                  /*__is_vector=*/std::false_type) noexcept
+{
+    return std::set_union(__first1, __last1, __first2, __last2, __result, __comp);
+}
+
+template <typename _IsVector>
+struct __BrickCopyConstruct
+{
+    template <typename _ForwardIterator, typename _OutputIterator>
+    _OutputIterator
+    operator()(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator __result)
+    {
+        return __brick_uninitialized_copy(__first, __last, __result, _IsVector());
+    }
+};
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _OutputIterator, class _Compare>
+_OutputIterator
+__brick_set_union(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2,
+                  _RandomAccessIterator2 __last2, _OutputIterator __result, _Compare __comp,
+                  /*__is_vector=*/std::true_type) noexcept
+{
+    _PSTL_PRAGMA_MESSAGE("Vectorized algorithm unimplemented, redirected to serial");
+    return std::set_union(__first1, __last1, __first2, __last2, __result, __comp);
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _OutputIterator,
+          class _Compare>
+_OutputIterator
+__pattern_set_union(_Tag, _ExecutionPolicy&&, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                    _ForwardIterator2 __first2, _ForwardIterator2 __last2, _OutputIterator __result,
+                    _Compare __comp) noexcept
+{
+    return __internal::__brick_set_union(__first1, __last1, __first2, __last2, __result, __comp,
+                                         typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _OutputIterator, class _Compare>
+_OutputIterator
+__pattern_set_union(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first1,
+                    _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2,
+                    _OutputIterator __result, _Compare __comp)
+{
+
+    const auto __n1 = __last1 - __first1;
+    const auto __n2 = __last2 - __first2;
+
+    // use serial algorithm
+    if (__n1 + __n2 <= __set_algo_cut_off)
+        return std::set_union(__first1, __last1, __first2, __last2, __result, __comp);
+
+    typedef typename std::iterator_traits<_OutputIterator>::value_type _Tp;
+    return __parallel_set_union_op(
+        __tag, std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __first2, __last2, __result, __comp,
+        [](_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2,
+           _RandomAccessIterator2 __last2, _Tp* __result, _Compare __comp)
+        {
+            return __pstl::__utils::__set_union_construct(__first1, __last1, __first2, __last2, __result, __comp,
+                                                          __BrickCopyConstruct<_IsVector>());
+        });
+}
+
+//------------------------------------------------------------------------
+// set_intersection
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _OutputIterator, class _Compare>
+_OutputIterator
+__brick_set_intersection(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+                         _ForwardIterator2 __last2, _OutputIterator __result, _Compare __comp,
+                         /*__is_vector=*/std::false_type) noexcept
+{
+    return std::set_intersection(__first1, __last1, __first2, __last2, __result, __comp);
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _RandomAccessIterator3, class _Compare>
+_RandomAccessIterator3
+__brick_set_intersection(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
+                         _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2,
+                         _RandomAccessIterator3 __result, _Compare __comp,
+                         /*__is_vector=*/std::true_type) noexcept
+{
+    _PSTL_PRAGMA_MESSAGE("Vectorized algorithm unimplemented, redirected to serial");
+    return std::set_intersection(__first1, __last1, __first2, __last2, __result, __comp);
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _OutputIterator,
+          class _Compare>
+_OutputIterator
+__pattern_set_intersection(_Tag, _ExecutionPolicy&&, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                           _ForwardIterator2 __first2, _ForwardIterator2 __last2, _OutputIterator __result,
+                           _Compare __comp) noexcept
+{
+    return __internal::__brick_set_intersection(__first1, __last1, __first2, __last2, __result, __comp,
+                                                typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _RandomAccessIterator3, class _Compare>
+_RandomAccessIterator3
+__pattern_set_intersection(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first1,
+                           _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2,
+                           _RandomAccessIterator2 __last2, _RandomAccessIterator3 __result, _Compare __comp)
+{
+    typedef typename std::iterator_traits<_RandomAccessIterator3>::value_type _Tp;
+    typedef typename std::iterator_traits<_RandomAccessIterator1>::difference_type _DifferenceType;
+
+    const auto __n1 = __last1 - __first1;
+    const auto __n2 = __last2 - __first2;
+
+    // intersection is empty
+    if (__n1 == 0 || __n2 == 0)
+        return __result;
+
+    // testing  whether the sequences are intersected
+    _RandomAccessIterator1 __left_bound_seq_1 = std::lower_bound(__first1, __last1, *__first2, __comp);
+    //{1} < {2}: seq 2 is wholly greater than seq 1, so, the intersection is empty
+    if (__left_bound_seq_1 == __last1)
+        return __result;
+
+    // testing  whether the sequences are intersected
+    _RandomAccessIterator2 __left_bound_seq_2 = std::lower_bound(__first2, __last2, *__first1, __comp);
+    //{2} < {1}: seq 1 is wholly greater than seq 2, so, the intersection is empty
+    if (__left_bound_seq_2 == __last2)
+        return __result;
+
+    const auto __m1 = __last1 - __left_bound_seq_1 + __n2;
+    if (__m1 > __set_algo_cut_off)
+    {
+        //we know proper offset due to [first1; left_bound_seq_1) < [first2; last2)
+        return __internal::__parallel_set_op(
+            __tag, std::forward<_ExecutionPolicy>(__exec), __left_bound_seq_1, __last1, __first2, __last2, __result,
+            __comp, [](_DifferenceType __n, _DifferenceType __m) { return std::min(__n, __m); },
+            [](_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2,
+               _RandomAccessIterator2 __last2, _Tp* __result, _Compare __comp) {
+                return __pstl::__utils::__set_intersection_construct(__first1, __last1, __first2, __last2, __result,
+                                                                     __comp);
+            });
+    }
+
+    const auto __m2 = __last2 - __left_bound_seq_2 + __n1;
+    if (__m2 > __set_algo_cut_off)
+    {
+        //we know proper offset due to [first2; left_bound_seq_2) < [first1; last1)
+        __result = __internal::__parallel_set_op(
+            __tag, std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __left_bound_seq_2, __last2, __result,
+            __comp, [](_DifferenceType __n, _DifferenceType __m) { return std::min(__n, __m); },
+            [](_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2,
+               _RandomAccessIterator2 __last2, _Tp* __result, _Compare __comp) {
+                return __pstl::__utils::__set_intersection_construct(__first2, __last2, __first1, __last1, __result,
+                                                                     __comp);
+            });
+        return __result;
+    }
+
+    // [left_bound_seq_1; last1) and [left_bound_seq_2; last2) - use serial algorithm
+    return std::set_intersection(__left_bound_seq_1, __last1, __left_bound_seq_2, __last2, __result, __comp);
+}
+
+//------------------------------------------------------------------------
+// set_difference
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _OutputIterator, class _Compare>
+_OutputIterator
+__brick_set_difference(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+                       _ForwardIterator2 __last2, _OutputIterator __result, _Compare __comp,
+                       /*__is_vector=*/std::false_type) noexcept
+{
+    return std::set_difference(__first1, __last1, __first2, __last2, __result, __comp);
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _RandomAccessIterator3, class _Compare>
+_RandomAccessIterator3
+__brick_set_difference(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2,
+                       _RandomAccessIterator2 __last2, _RandomAccessIterator3 __result, _Compare __comp,
+                       /*__is_vector=*/std::true_type) noexcept
+{
+    _PSTL_PRAGMA_MESSAGE("Vectorized algorithm unimplemented, redirected to serial");
+    return std::set_difference(__first1, __last1, __first2, __last2, __result, __comp);
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _OutputIterator,
+          class _Compare>
+_OutputIterator
+__pattern_set_difference(_Tag, _ExecutionPolicy&&, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                         _ForwardIterator2 __first2, _ForwardIterator2 __last2, _OutputIterator __result,
+                         _Compare __comp) noexcept
+{
+    return __internal::__brick_set_difference(__first1, __last1, __first2, __last2, __result, __comp,
+                                              typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _RandomAccessIterator3, class _Compare>
+_RandomAccessIterator3
+__pattern_set_difference(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first1,
+                         _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2,
+                         _RandomAccessIterator2 __last2, _RandomAccessIterator3 __result, _Compare __comp)
+{
+    typedef typename std::iterator_traits<_RandomAccessIterator3>::value_type _Tp;
+    typedef typename std::iterator_traits<_RandomAccessIterator1>::difference_type _DifferenceType;
+
+    const auto __n1 = __last1 - __first1;
+    const auto __n2 = __last2 - __first2;
+
+    // {} \ {2}: the difference is empty
+    if (__n1 == 0)
+        return __result;
+
+    // {1} \ {}: parallel copying just first sequence
+    if (__n2 == 0)
+        return __internal::__pattern_walk2_brick(
+            __tag, std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __result,
+            [](_RandomAccessIterator1 __begin, _RandomAccessIterator1 __end, _RandomAccessIterator3 __res)
+            { return __internal::__brick_copy(__begin, __end, __res, _IsVector{}); });
+
+    // testing  whether the sequences are intersected
+    _RandomAccessIterator1 __left_bound_seq_1 = std::lower_bound(__first1, __last1, *__first2, __comp);
+    //{1} < {2}: seq 2 is wholly greater than seq 1, so, parallel copying just first sequence
+    if (__left_bound_seq_1 == __last1)
+        return __internal::__pattern_walk2_brick(
+            __tag, std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __result,
+            [](_RandomAccessIterator1 __begin, _RandomAccessIterator1 __end, _RandomAccessIterator3 __res)
+            { return __internal::__brick_copy(__begin, __end, __res, _IsVector{}); });
+
+    // testing  whether the sequences are intersected
+    _RandomAccessIterator2 __left_bound_seq_2 = std::lower_bound(__first2, __last2, *__first1, __comp);
+    //{2} < {1}: seq 1 is wholly greater than seq 2, so, parallel copying just first sequence
+    if (__left_bound_seq_2 == __last2)
+        return __internal::__pattern_walk2_brick(
+            __tag, std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __result,
+            [](_RandomAccessIterator1 __begin, _RandomAccessIterator1 __end, _RandomAccessIterator3 __res)
+            { return __internal::__brick_copy(__begin, __end, __res, _IsVector{}); });
+
+    if (__n1 + __n2 > __set_algo_cut_off)
+        return __parallel_set_op(
+            __tag, std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __first2, __last2, __result, __comp,
+            [](_DifferenceType __n, _DifferenceType) { return __n; },
+            [](_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2,
+               _RandomAccessIterator2 __last2, _Tp* __result, _Compare __comp)
+            {
+                return __pstl::__utils::__set_difference_construct(__first1, __last1, __first2, __last2, __result,
+                                                                   __comp, __BrickCopyConstruct<_IsVector>());
+            });
+
+    // use serial algorithm
+    return std::set_difference(__first1, __last1, __first2, __last2, __result, __comp);
+}
+
+//------------------------------------------------------------------------
+// set_symmetric_difference
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _OutputIterator, class _Compare>
+_OutputIterator
+__brick_set_symmetric_difference(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+                                 _ForwardIterator2 __last2, _OutputIterator __result, _Compare __comp,
+                                 /*__is_vector=*/std::false_type) noexcept
+{
+    return std::set_symmetric_difference(__first1, __last1, __first2, __last2, __result, __comp);
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _RandomAccessIterator3, class _Compare>
+_RandomAccessIterator3
+__brick_set_symmetric_difference(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
+                                 _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2,
+                                 _RandomAccessIterator3 __result, _Compare __comp,
+                                 /*__is_vector=*/std::true_type) noexcept
+{
+    _PSTL_PRAGMA_MESSAGE("Vectorized algorithm unimplemented, redirected to serial");
+    return std::set_symmetric_difference(__first1, __last1, __first2, __last2, __result, __comp);
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _OutputIterator,
+          class _Compare>
+_OutputIterator
+__pattern_set_symmetric_difference(_Tag, _ExecutionPolicy&&, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                                   _ForwardIterator2 __first2, _ForwardIterator2 __last2, _OutputIterator __result,
+                                   _Compare __comp) noexcept
+{
+    return __internal::__brick_set_symmetric_difference(__first1, __last1, __first2, __last2, __result, __comp,
+                                                        typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _RandomAccessIterator3, class _Compare>
+_RandomAccessIterator3
+__pattern_set_symmetric_difference(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec,
+                                   _RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
+                                   _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2,
+                                   _RandomAccessIterator3 __result, _Compare __comp)
+{
+
+    const auto __n1 = __last1 - __first1;
+    const auto __n2 = __last2 - __first2;
+
+    // use serial algorithm
+    if (__n1 + __n2 <= __set_algo_cut_off)
+        return std::set_symmetric_difference(__first1, __last1, __first2, __last2, __result, __comp);
+
+    typedef typename std::iterator_traits<_RandomAccessIterator3>::value_type _Tp;
+    return __internal::__parallel_set_union_op(
+        __tag, std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __first2, __last2, __result, __comp,
+        [](_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2,
+           _RandomAccessIterator2 __last2, _Tp* __result, _Compare __comp)
+        {
+            return __pstl::__utils::__set_symmetric_difference_construct(__first1, __last1, __first2, __last2, __result,
+                                                                         __comp, __BrickCopyConstruct<_IsVector>());
+        });
+}
+
+//------------------------------------------------------------------------
+// is_heap_until
+//------------------------------------------------------------------------
+
+template <class _RandomAccessIterator, class _Compare>
+_RandomAccessIterator
+__brick_is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
+                      /* __is_vector = */ std::false_type) noexcept
+{
+    return std::is_heap_until(__first, __last, __comp);
+}
+
+template <class _RandomAccessIterator, class _Compare>
+_RandomAccessIterator
+__brick_is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
+                      /* __is_vector = */ std::true_type) noexcept
+{
+    if (__last - __first < 2)
+        return __last;
+    typedef typename std::iterator_traits<_RandomAccessIterator>::difference_type _SizeType;
+    return __unseq_backend::__simd_first(
+        __first, _SizeType(0), __last - __first,
+        [&__comp](_RandomAccessIterator __it, _SizeType __i) { return __comp(__it[(__i - 1) / 2], __it[__i]); });
+}
+
+template <class _Tag, class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+_RandomAccessIterator
+__pattern_is_heap_until(_Tag, _ExecutionPolicy&&, _RandomAccessIterator __first, _RandomAccessIterator __last,
+                        _Compare __comp) noexcept
+{
+    return __internal::__brick_is_heap_until(__first, __last, __comp, typename _Tag::__is_vector{});
+}
+
+template <class _RandomAccessIterator, class _DifferenceType, class _Compare>
+_RandomAccessIterator
+__is_heap_until_local(_RandomAccessIterator __first, _DifferenceType __begin, _DifferenceType __end, _Compare __comp,
+                      /* __is_vector = */ std::false_type) noexcept
+{
+    _DifferenceType __i = __begin;
+    for (; __i < __end; ++__i)
+    {
+        if (__comp(__first[(__i - 1) / 2], __first[__i]))
+        {
+            break;
+        }
+    }
+    return __first + __i;
+}
+
+template <class _RandomAccessIterator, class _DifferenceType, class _Compare>
+_RandomAccessIterator
+__is_heap_until_local(_RandomAccessIterator __first, _DifferenceType __begin, _DifferenceType __end, _Compare __comp,
+                      /* __is_vector = */ std::true_type) noexcept
+{
+    return __unseq_backend::__simd_first(
+        __first, __begin, __end,
+        [&__comp](_RandomAccessIterator __it, _DifferenceType __i) { return __comp(__it[(__i - 1) / 2], __it[__i]); });
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+_RandomAccessIterator
+__pattern_is_heap_until(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                        _RandomAccessIterator __last, _Compare __comp) noexcept
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    if (__last - __first < 2)
+        return __last;
+
+    return __internal::__except_handler(
+        [&]()
+        {
+            return __parallel_find(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                [__first, __comp](_RandomAccessIterator __i, _RandomAccessIterator __j) {
+                    return __internal::__is_heap_until_local(__first, __i - __first, __j - __first, __comp,
+                                                             _IsVector{});
+                },
+                std::less<typename std::iterator_traits<_RandomAccessIterator>::difference_type>(), /*is_first=*/true);
+        });
+}
+
+//------------------------------------------------------------------------
+// min_element
+//------------------------------------------------------------------------
+
+template <typename _ForwardIterator, typename _Compare>
+_ForwardIterator
+__brick_min_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp,
+                    /* __is_vector = */ std::false_type) noexcept
+{
+    return std::min_element(__first, __last, __comp);
+}
+
+template <typename _RandomAccessIterator, typename _Compare>
+_RandomAccessIterator
+__brick_min_element(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
+                    /* __is_vector = */ std::true_type) noexcept
+{
+#if defined(_PSTL_UDR_PRESENT)
+    return __unseq_backend::__simd_min_element(__first, __last - __first, __comp);
+#else
+    return std::min_element(__first, __last, __comp);
+#endif
+}
+
+template <typename _Tag, typename _ExecutionPolicy, typename _ForwardIterator, typename _Compare>
+_ForwardIterator
+__pattern_min_element(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last,
+                      _Compare __comp) noexcept
+{
+    return __internal::__brick_min_element(__first, __last, __comp, typename _Tag::__is_vector{});
+}
+
+template <typename _IsVector, typename _ExecutionPolicy, typename _RandomAccessIterator, typename _Compare>
+_RandomAccessIterator
+__pattern_min_element(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                      _RandomAccessIterator __last, _Compare __comp)
+{
+    if (__first == __last)
+        return __last;
+
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    return __internal::__except_handler(
+        [&]()
+        {
+            return __par_backend::__parallel_reduce(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first + 1, __last, __first,
+                [=](_RandomAccessIterator __begin, _RandomAccessIterator __end,
+                    _RandomAccessIterator __init) -> _RandomAccessIterator
+                {
+                    const _RandomAccessIterator subresult =
+                        __internal::__brick_min_element(__begin, __end, __comp, _IsVector{});
+                    return __internal::__cmp_iterators_by_values(__init, subresult, __comp);
+                },
+                [=](_RandomAccessIterator __it1, _RandomAccessIterator __it2) -> _RandomAccessIterator
+                { return __internal::__cmp_iterators_by_values(__it1, __it2, __comp); });
+        });
+}
+
+//------------------------------------------------------------------------
+// minmax_element
+//------------------------------------------------------------------------
+
+template <typename _ForwardIterator, typename _Compare>
+std::pair<_ForwardIterator, _ForwardIterator>
+__brick_minmax_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp,
+                       /* __is_vector = */ std::false_type) noexcept
+{
+    return std::minmax_element(__first, __last, __comp);
+}
+
+template <typename _RandomAccessIterator, typename _Compare>
+std::pair<_RandomAccessIterator, _RandomAccessIterator>
+__brick_minmax_element(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
+                       /* __is_vector = */ std::true_type) noexcept
+{
+#if defined(_PSTL_UDR_PRESENT)
+    return __unseq_backend::__simd_minmax_element(__first, __last - __first, __comp);
+#else
+    return std::minmax_element(__first, __last, __comp);
+#endif
+}
+
+template <typename _Tag, typename _ExecutionPolicy, typename _ForwardIterator, typename _Compare>
+std::pair<_ForwardIterator, _ForwardIterator>
+__pattern_minmax_element(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last,
+                         _Compare __comp) noexcept
+{
+    return __internal::__brick_minmax_element(__first, __last, __comp, typename _Tag::__is_vector{});
+}
+
+template <typename _IsVector, typename _ExecutionPolicy, typename _RandomAccessIterator, typename _Compare>
+std::pair<_RandomAccessIterator, _RandomAccessIterator>
+__pattern_minmax_element(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                         _RandomAccessIterator __last, _Compare __comp)
+{
+    if (__first == __last)
+        return std::make_pair(__first, __first);
+
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    return __internal::__except_handler([&]() {
+        typedef std::pair<_RandomAccessIterator, _RandomAccessIterator> _Result;
+
+        return __par_backend::__parallel_reduce(
+            __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first + 1, __last,
+            std::make_pair(__first, __first),
+            [=](_RandomAccessIterator __begin, _RandomAccessIterator __end, _Result __init) -> _Result
+            {
+                const _Result __subresult = __internal::__brick_minmax_element(__begin, __end, __comp, _IsVector{});
+                return std::make_pair(
+                    __internal::__cmp_iterators_by_values(__subresult.first, __init.first, __comp),
+                    __internal::__cmp_iterators_by_values(__init.second, __subresult.second, std::not_fn(__comp)));
+            },
+            [=](_Result __p1, _Result __p2) -> _Result
+            {
+                return std::make_pair(
+                    __internal::__cmp_iterators_by_values(__p1.first, __p2.first, __comp),
+                    __internal::__cmp_iterators_by_values(__p2.second, __p1.second, std::not_fn(__comp)));
+            });
+    });
+}
+
+//------------------------------------------------------------------------
+// mismatch
+//------------------------------------------------------------------------
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+std::pair<_ForwardIterator1, _ForwardIterator2>
+__mismatch_serial(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+                  _ForwardIterator2 __last2, _BinaryPredicate __pred)
+{
+#if defined(_PSTL_CPP14_2RANGE_MISMATCH_EQUAL_PRESENT)
+    return std::mismatch(__first1, __last1, __first2, __last2, __pred);
+#else
+    for (; __first1 != __last1 && __first2 != __last2 && __pred(*__first1, *__first2); ++__first1, ++__first2)
+    {
+    }
+    return std::make_pair(__first1, __first2);
+#endif
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _Predicate>
+std::pair<_ForwardIterator1, _ForwardIterator2>
+__brick_mismatch(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+                 _ForwardIterator2 __last2, _Predicate __pred, /* __is_vector = */ std::false_type) noexcept
+{
+    return __mismatch_serial(__first1, __last1, __first2, __last2, __pred);
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _Predicate>
+std::pair<_RandomAccessIterator1, _RandomAccessIterator2>
+__brick_mismatch(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2,
+                 _RandomAccessIterator2 __last2, _Predicate __pred, /* __is_vector = */ std::true_type) noexcept
+{
+    auto __n = std::min(__last1 - __first1, __last2 - __first2);
+    return __unseq_backend::__simd_first(__first1, __n, __first2, std::not_fn(__pred));
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Predicate>
+std::pair<_ForwardIterator1, _ForwardIterator2>
+__pattern_mismatch(_Tag, _ExecutionPolicy&&, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                   _ForwardIterator2 __first2, _ForwardIterator2 __last2, _Predicate __pred) noexcept
+{
+    return __internal::__brick_mismatch(__first1, __last1, __first2, __last2, __pred, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _Predicate>
+std::pair<_RandomAccessIterator1, _RandomAccessIterator2>
+__pattern_mismatch(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first1,
+                   _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2,
+                   _Predicate __pred) noexcept
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    return __internal::__except_handler([&]() {
+        auto __n = std::min(__last1 - __first1, __last2 - __first2);
+        auto __result = __internal::__parallel_find(
+            __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first1, __first1 + __n,
+            [__first1, __first2, __pred](_RandomAccessIterator1 __i, _RandomAccessIterator1 __j)
+            {
+                return __internal::__brick_mismatch(__i, __j, __first2 + (__i - __first1), __first2 + (__j - __first1),
+                                                    __pred, _IsVector{})
+                    .first;
+            },
+            std::less<typename std::iterator_traits<_RandomAccessIterator1>::difference_type>(), /*is_first=*/true);
+        return std::make_pair(__result, __first2 + (__result - __first1));
+    });
+}
+
+//------------------------------------------------------------------------
+// lexicographical_compare
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _Compare>
+bool
+__brick_lexicographical_compare(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+                                _ForwardIterator2 __last2, _Compare __comp,
+                                /* __is_vector = */ std::false_type) noexcept
+{
+    return std::lexicographical_compare(__first1, __last1, __first2, __last2, __comp);
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _Compare>
+bool
+__brick_lexicographical_compare(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
+                                _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _Compare __comp,
+                                /* __is_vector = */ std::true_type) noexcept
+{
+    if (__first2 == __last2)
+    { // if second sequence is empty
+        return false;
+    }
+    else if (__first1 == __last1)
+    { // if first sequence is empty
+        return true;
+    }
+    else
+    {
+        typedef typename std::iterator_traits<_RandomAccessIterator1>::reference ref_type1;
+        typedef typename std::iterator_traits<_RandomAccessIterator2>::reference ref_type2;
+        --__last1;
+        --__last2;
+        auto __n = std::min(__last1 - __first1, __last2 - __first2);
+        std::pair<_RandomAccessIterator1, _RandomAccessIterator2> __result = __unseq_backend::__simd_first(
+            __first1, __n, __first2, [__comp](const ref_type1 __x, const ref_type2 __y) mutable {
+                return __comp(__x, __y) || __comp(__y, __x);
+            });
+
+        if (__result.first == __last1 && __result.second != __last2)
+        { // if first sequence shorter than second
+            return !__comp(*__result.second, *__result.first);
+        }
+        else
+        { // if second sequence shorter than first or both have the same number of elements
+            return __comp(*__result.first, *__result.second);
+        }
+    }
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Compare>
+bool
+__pattern_lexicographical_compare(_Tag, _ExecutionPolicy&&, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                                  _ForwardIterator2 __first2, _ForwardIterator2 __last2, _Compare __comp) noexcept
+{
+    return __internal::__brick_lexicographical_compare(__first1, __last1, __first2, __last2, __comp,
+                                                       typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _Compare>
+bool
+__pattern_lexicographical_compare(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec,
+                                  _RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
+                                  _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2,
+                                  _Compare __comp) noexcept
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    if (__first2 == __last2)
+    { // if second sequence is empty
+        return false;
+    }
+    else if (__first1 == __last1)
+    { // if first sequence is empty
+        return true;
+    }
+    else
+    {
+        typedef typename std::iterator_traits<_RandomAccessIterator1>::reference _RefType1;
+        typedef typename std::iterator_traits<_RandomAccessIterator2>::reference _RefType2;
+        --__last1;
+        --__last2;
+        auto __n = std::min(__last1 - __first1, __last2 - __first2);
+        auto __result = __internal::__parallel_find(
+            __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first1, __first1 + __n,
+            [__first1, __first2, &__comp](_RandomAccessIterator1 __i, _RandomAccessIterator1 __j)
+            {
+                return __internal::__brick_mismatch(
+                           __i, __j, __first2 + (__i - __first1), __first2 + (__j - __first1),
+                           [&__comp](const _RefType1 __x, const _RefType2 __y)
+                           { return !__comp(__x, __y) && !__comp(__y, __x); },
+                           _IsVector{})
+                    .first;
+            },
+            std::less<typename std::iterator_traits<_RandomAccessIterator1>::difference_type>(), /*is_first=*/true);
+
+        if (__result == __last1 && __first2 + (__result - __first1) != __last2)
+        { // if first sequence shorter than second
+            return !__comp(*(__first2 + (__result - __first1)), *__result);
+        }
+        else
+        { // if second sequence shorter than first or both have the same number of elements
+            return __comp(*__result, *(__first2 + (__result - __first1)));
+        }
+    }
+}
+
+} // namespace __internal
+} // namespace __pstl
+
+_PSTL_HIDE_FROM_ABI_POP
+
+#endif /* _PSTL_ALGORITHM_IMPL_H */
diff --git a/pstl/include/pstl/internal/execution_defs.h b/pstl/include/pstl/internal/execution_defs.h
new file mode 100644
index 0000000..d7c4126
--- /dev/null
+++ b/pstl/include/pstl/internal/execution_defs.h
@@ -0,0 +1,100 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_EXECUTION_POLICY_DEFS_H
+#define _PSTL_EXECUTION_POLICY_DEFS_H
+
+#include <type_traits>
+
+#include "pstl_config.h"
+
+_PSTL_HIDE_FROM_ABI_PUSH
+
+namespace __pstl
+{
+namespace execution
+{
+inline namespace v1
+{
+
+// 2.4, Sequential execution policy
+class sequenced_policy
+{
+};
+
+// 2.5, Parallel execution policy
+class parallel_policy
+{
+};
+
+// 2.6, Parallel+Vector execution policy
+class parallel_unsequenced_policy
+{
+};
+
+class unsequenced_policy
+{
+};
+
+// 2.8, Execution policy objects
+constexpr sequenced_policy seq{};
+constexpr parallel_policy par{};
+constexpr parallel_unsequenced_policy par_unseq{};
+constexpr unsequenced_policy unseq{};
+
+// 2.3, Execution policy type trait
+template <class T>
+struct is_execution_policy : std::false_type
+{
+};
+
+template <>
+struct is_execution_policy<__pstl::execution::sequenced_policy> : std::true_type
+{
+};
+template <>
+struct is_execution_policy<__pstl::execution::parallel_policy> : std::true_type
+{
+};
+template <>
+struct is_execution_policy<__pstl::execution::parallel_unsequenced_policy> : std::true_type
+{
+};
+template <>
+struct is_execution_policy<__pstl::execution::unsequenced_policy> : std::true_type
+{
+};
+
+#if defined(_PSTL_CPP14_VARIABLE_TEMPLATES_PRESENT)
+template <class T>
+constexpr bool is_execution_policy_v = __pstl::execution::is_execution_policy<T>::value;
+#endif
+
+} // namespace v1
+} // namespace execution
+
+namespace __internal
+{
+template <class ExecPolicy, class T>
+using __enable_if_execution_policy =
+    typename std::enable_if<__pstl::execution::is_execution_policy<typename std::decay<ExecPolicy>::type>::value,
+                            T>::type;
+
+template <class _IsVector>
+struct __serial_tag;
+template <class _IsVector>
+struct __parallel_tag;
+
+} // namespace __internal
+
+} // namespace __pstl
+
+_PSTL_HIDE_FROM_ABI_POP
+
+#endif /* _PSTL_EXECUTION_POLICY_DEFS_H */
diff --git a/pstl/include/pstl/internal/execution_impl.h b/pstl/include/pstl/internal/execution_impl.h
new file mode 100644
index 0000000..5dc622b
--- /dev/null
+++ b/pstl/include/pstl/internal/execution_impl.h
@@ -0,0 +1,105 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_EXECUTION_IMPL_H
+#define _PSTL_EXECUTION_IMPL_H
+
+#include <iterator>
+#include <type_traits>
+
+#include "pstl_config.h"
+#include "execution_defs.h"
+
+_PSTL_HIDE_FROM_ABI_PUSH
+
+namespace __pstl
+{
+namespace __internal
+{
+
+template <typename _IteratorTag, typename... _IteratorTypes>
+using __are_iterators_of = std::conjunction<
+    std::is_base_of<_IteratorTag, typename std::iterator_traits<std::decay_t<_IteratorTypes>>::iterator_category>...>;
+
+template <typename... _IteratorTypes>
+using __are_random_access_iterators = __are_iterators_of<std::random_access_iterator_tag, _IteratorTypes...>;
+
+struct __serial_backend_tag
+{
+};
+struct __tbb_backend_tag
+{
+};
+struct __openmp_backend_tag
+{
+};
+
+#if defined(_PSTL_PAR_BACKEND_TBB)
+using __par_backend_tag = __tbb_backend_tag;
+#elif defined(_PSTL_PAR_BACKEND_OPENMP)
+using __par_backend_tag = __openmp_backend_tag;
+#elif defined(_PSTL_PAR_BACKEND_SERIAL)
+using __par_backend_tag = __serial_backend_tag;
+#else
+#    error "A parallel backend must be specified";
+#endif
+
+template <class _IsVector>
+struct __serial_tag
+{
+    using __is_vector = _IsVector;
+};
+
+template <class _IsVector>
+struct __parallel_tag
+{
+    using __is_vector = _IsVector;
+    // backend tag can be change depending on
+    // TBB availability in the environment
+    using __backend_tag = __par_backend_tag;
+};
+
+template <class _IsVector, class... _IteratorTypes>
+using __tag_type = typename std::conditional<__internal::__are_random_access_iterators<_IteratorTypes...>::value,
+                                             __parallel_tag<_IsVector>, __serial_tag<_IsVector>>::type;
+
+template <class... _IteratorTypes>
+__serial_tag</*_IsVector = */ std::false_type>
+__select_backend(__pstl::execution::sequenced_policy, _IteratorTypes&&...)
+{
+    return {};
+}
+
+template <class... _IteratorTypes>
+__serial_tag<__internal::__are_random_access_iterators<_IteratorTypes...>>
+__select_backend(__pstl::execution::unsequenced_policy, _IteratorTypes&&...)
+{
+    return {};
+}
+
+template <class... _IteratorTypes>
+__tag_type</*_IsVector = */ std::false_type, _IteratorTypes...>
+__select_backend(__pstl::execution::parallel_policy, _IteratorTypes&&...)
+{
+    return {};
+}
+
+template <class... _IteratorTypes>
+__tag_type<__internal::__are_random_access_iterators<_IteratorTypes...>, _IteratorTypes...>
+__select_backend(__pstl::execution::parallel_unsequenced_policy, _IteratorTypes&&...)
+{
+    return {};
+}
+
+} // namespace __internal
+} // namespace __pstl
+
+_PSTL_HIDE_FROM_ABI_POP
+
+#endif /* _PSTL_EXECUTION_IMPL_H */
diff --git a/pstl/include/pstl/internal/glue_algorithm_defs.h b/pstl/include/pstl/internal/glue_algorithm_defs.h
new file mode 100644
index 0000000..28a7f92
--- /dev/null
+++ b/pstl/include/pstl/internal/glue_algorithm_defs.h
@@ -0,0 +1,558 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_GLUE_ALGORITHM_DEFS_H
+#define _PSTL_GLUE_ALGORITHM_DEFS_H
+
+#include <functional>
+#include <iterator>
+
+#include "execution_defs.h"
+#include "pstl_config.h"
+
+_PSTL_HIDE_FROM_ABI_PUSH
+
+namespace std
+{
+
+// [alg.any_of]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Predicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+any_of(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred);
+
+// [alg.all_of]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Predicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+all_of(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred);
+
+// [alg.none_of]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Predicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+none_of(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred);
+
+// [alg.foreach]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Function>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+for_each(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Function __f);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Function>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+for_each_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _Size __n, _Function __f);
+
+// [alg.find]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Predicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+find_if(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Predicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+find_if_not(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+find(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value);
+
+// [alg.find.end]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator1>
+find_end(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __s_first,
+         _ForwardIterator2 __s_last, _BinaryPredicate __pred);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator1>
+find_end(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __s_first,
+         _ForwardIterator2 __s_last);
+
+// [alg.find_first_of]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator1>
+find_first_of(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+              _ForwardIterator2 __s_first, _ForwardIterator2 __s_last, _BinaryPredicate __pred);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator1>
+find_first_of(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+              _ForwardIterator2 __s_first, _ForwardIterator2 __s_last);
+
+// [alg.adjacent_find]
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+adjacent_find(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _BinaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+adjacent_find(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred);
+
+// [alg.count]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy,
+                                                 typename iterator_traits<_ForwardIterator>::difference_type>
+count(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Predicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy,
+                                                 typename iterator_traits<_ForwardIterator>::difference_type>
+count_if(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred);
+
+// [alg.search]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator1>
+search(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __s_first,
+       _ForwardIterator2 __s_last, _BinaryPredicate __pred);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator1>
+search(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __s_first,
+       _ForwardIterator2 __s_last);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Tp, class _BinaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+search_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Size __count,
+         const _Tp& __value, _BinaryPredicate __pred);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+search_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Size __count,
+         const _Tp& __value);
+
+// [alg.copy]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+copy(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __result);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _Size, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+copy_n(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _Size __n, _ForwardIterator2 __result);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Predicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+copy_if(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 result,
+        _Predicate __pred);
+
+// [alg.swap]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+swap_ranges(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+            _ForwardIterator2 __first2);
+
+// [alg.transform]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _UnaryOperation>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+transform(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __result,
+          _UnaryOperation __op);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator,
+          class _BinaryOperation>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+transform(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+          _ForwardIterator __result, _BinaryOperation __op);
+
+// [alg.replace]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _UnaryPredicate, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+replace_if(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _UnaryPredicate __pred,
+           const _Tp& __new_value);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+replace(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __old_value,
+        const _Tp& __new_value);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _UnaryPredicate, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+replace_copy_if(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+                _ForwardIterator2 __result, _UnaryPredicate __pred, const _Tp& __new_value);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+replace_copy(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __result,
+             const _Tp& __old_value, const _Tp& __new_value);
+
+// [alg.fill]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+fill(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+fill_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _Size __count, const _Tp& __value);
+
+// [alg.generate]
+template <class _ExecutionPolicy, class _ForwardIterator, class _Generator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+generate(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Generator __g);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Generator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+generate_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _Size count, _Generator __g);
+
+// [alg.remove]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Predicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+remove_copy_if(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+               _ForwardIterator2 __result, _Predicate __pred);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+remove_copy(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __result,
+            const _Tp& __value);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _UnaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+remove_if(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _UnaryPredicate __pred);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+remove(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value);
+
+// [alg.unique]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _BinaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+unique(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred);
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+unique(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+unique_copy(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __result,
+            _BinaryPredicate __pred);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+unique_copy(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __result);
+
+// [alg.reverse]
+
+template <class _ExecutionPolicy, class _BidirectionalIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+reverse(_ExecutionPolicy&& __exec, _BidirectionalIterator __first, _BidirectionalIterator __last);
+
+template <class _ExecutionPolicy, class _BidirectionalIterator, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+reverse_copy(_ExecutionPolicy&& __exec, _BidirectionalIterator __first, _BidirectionalIterator __last,
+             _ForwardIterator __d_first);
+
+// [alg.rotate]
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+rotate(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+rotate_copy(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __middle, _ForwardIterator1 __last,
+            _ForwardIterator2 __result);
+
+// [alg.partitions]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _UnaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+is_partitioned(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _UnaryPredicate __pred);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _UnaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+partition(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _UnaryPredicate __pred);
+
+template <class _ExecutionPolicy, class _BidirectionalIterator, class _UnaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _BidirectionalIterator>
+stable_partition(_ExecutionPolicy&& __exec, _BidirectionalIterator __first, _BidirectionalIterator __last,
+                 _UnaryPredicate __pred);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _ForwardIterator1, class _ForwardIterator2,
+          class _UnaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, std::pair<_ForwardIterator1, _ForwardIterator2>>
+partition_copy(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last,
+               _ForwardIterator1 __out_true, _ForwardIterator2 __out_false, _UnaryPredicate __pred);
+
+// [alg.sort]
+
+template <class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+sort(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp);
+
+template <class _ExecutionPolicy, class _RandomAccessIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+sort(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last);
+
+// [stable.sort]
+
+template <class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+stable_sort(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp);
+
+template <class _ExecutionPolicy, class _RandomAccessIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+stable_sort(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last);
+
+// [mismatch]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, std::pair<_ForwardIterator1, _ForwardIterator2>>
+mismatch(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+         _ForwardIterator2 __last2, _BinaryPredicate __pred);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, std::pair<_ForwardIterator1, _ForwardIterator2>>
+mismatch(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+         _BinaryPredicate __pred);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, std::pair<_ForwardIterator1, _ForwardIterator2>>
+mismatch(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+         _ForwardIterator2 __last2);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, std::pair<_ForwardIterator1, _ForwardIterator2>>
+mismatch(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2);
+
+// [alg.equal]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+equal(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+      _BinaryPredicate __p);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+equal(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+equal(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+      _ForwardIterator2 __last2, _BinaryPredicate __p);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+equal(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+      _ForwardIterator2 __last2);
+
+// [alg.move]
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+move(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __d_first);
+
+// [partial.sort]
+
+template <class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+partial_sort(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __middle,
+             _RandomAccessIterator __last, _Compare __comp);
+
+template <class _ExecutionPolicy, class _RandomAccessIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+partial_sort(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __middle,
+             _RandomAccessIterator __last);
+
+// [partial.sort.copy]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _RandomAccessIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _RandomAccessIterator>
+partial_sort_copy(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last,
+                  _RandomAccessIterator __d_first, _RandomAccessIterator __d_last, _Compare __comp);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _RandomAccessIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _RandomAccessIterator>
+partial_sort_copy(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last,
+                  _RandomAccessIterator __d_first, _RandomAccessIterator __d_last);
+
+// [is.sorted]
+template <class _ExecutionPolicy, class _ForwardIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+is_sorted_until(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Compare __comp);
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+is_sorted_until(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+is_sorted(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Compare __comp);
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+is_sorted(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last);
+
+// [alg.nth.element]
+
+template <class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+nth_element(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __nth,
+            _RandomAccessIterator __last, _Compare __comp);
+
+template <class _ExecutionPolicy, class _RandomAccessIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+nth_element(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __nth,
+            _RandomAccessIterator __last);
+
+// [alg.merge]
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator,
+          class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+merge(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+      _ForwardIterator2 __last2, _ForwardIterator __d_first, _Compare __comp);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+merge(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+      _ForwardIterator2 __last2, _ForwardIterator __d_first);
+
+template <class _ExecutionPolicy, class _BidirectionalIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+inplace_merge(_ExecutionPolicy&& __exec, _BidirectionalIterator __first, _BidirectionalIterator __middle,
+              _BidirectionalIterator __last, _Compare __comp);
+
+template <class _ExecutionPolicy, class _BidirectionalIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+inplace_merge(_ExecutionPolicy&& __exec, _BidirectionalIterator __first, _BidirectionalIterator __middle,
+              _BidirectionalIterator __last);
+
+// [includes]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+includes(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+         _ForwardIterator2 __last2, _Compare __comp);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+includes(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+         _ForwardIterator2 __last2);
+
+// [set.union]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator,
+          class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+set_union(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+          _ForwardIterator2 __last2, _ForwardIterator __result, _Compare __comp);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+set_union(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+          _ForwardIterator2 __last2, _ForwardIterator __result);
+
+// [set.intersection]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator,
+          class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+set_intersection(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                 _ForwardIterator2 __first2, _ForwardIterator2 __last2, _ForwardIterator __result, _Compare __comp);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+set_intersection(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                 _ForwardIterator2 __first2, _ForwardIterator2 __last2, _ForwardIterator __result);
+
+// [set.difference]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator,
+          class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+set_difference(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+               _ForwardIterator2 __first2, _ForwardIterator2 __last2, _ForwardIterator __result, _Compare __comp);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+set_difference(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+               _ForwardIterator2 __first2, _ForwardIterator2 __last2, _ForwardIterator __result);
+
+// [set.symmetric.difference]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator,
+          class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+set_symmetric_difference(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                         _ForwardIterator2 __first2, _ForwardIterator2 __last2, _ForwardIterator result,
+                         _Compare __comp);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+set_symmetric_difference(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                         _ForwardIterator2 __first2, _ForwardIterator2 __last2, _ForwardIterator __result);
+
+// [is.heap]
+template <class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _RandomAccessIterator>
+is_heap_until(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp);
+
+template <class _ExecutionPolicy, class _RandomAccessIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _RandomAccessIterator>
+is_heap_until(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last);
+
+template <class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+is_heap(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp);
+
+template <class _ExecutionPolicy, class _RandomAccessIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+is_heap(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last);
+
+// [alg.min.max]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+min_element(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Compare __comp);
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+min_element(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+max_element(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Compare __comp);
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+max_element(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, std::pair<_ForwardIterator, _ForwardIterator>>
+minmax_element(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Compare __comp);
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, std::pair<_ForwardIterator, _ForwardIterator>>
+minmax_element(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last);
+
+// [alg.lex.comparison]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+lexicographical_compare(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                        _ForwardIterator2 __first2, _ForwardIterator2 __last2, _Compare __comp);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+lexicographical_compare(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                        _ForwardIterator2 __first2, _ForwardIterator2 __last2);
+
+} // namespace std
+
+_PSTL_HIDE_FROM_ABI_POP
+
+#endif /* _PSTL_GLUE_ALGORITHM_DEFS_H */
diff --git a/pstl/include/pstl/internal/glue_algorithm_impl.h b/pstl/include/pstl/internal/glue_algorithm_impl.h
new file mode 100644
index 0000000..fb0c19d
--- /dev/null
+++ b/pstl/include/pstl/internal/glue_algorithm_impl.h
@@ -0,0 +1,1108 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_GLUE_ALGORITHM_IMPL_H
+#define _PSTL_GLUE_ALGORITHM_IMPL_H
+
+#include <functional>
+
+#include "pstl_config.h"
+
+#include "execution_defs.h"
+#include "utils.h"
+#include "algorithm_fwd.h"
+#include "numeric_fwd.h" /* count and count_if use __pattern_transform_reduce */
+
+#include "execution_impl.h"
+
+_PSTL_HIDE_FROM_ABI_PUSH
+
+namespace std
+{
+
+// [alg.any_of]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Predicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+any_of(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    return __pstl::__internal::__pattern_any_of(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                                __pred);
+}
+
+// [alg.all_of]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Pred>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+all_of(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Pred __pred)
+{
+    return !std::any_of(std::forward<_ExecutionPolicy>(__exec), __first, __last, std::not_fn(__pred));
+}
+
+// [alg.none_of]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Predicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+none_of(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
+{
+    return !std::any_of(std::forward<_ExecutionPolicy>(__exec), __first, __last, __pred);
+}
+
+// [alg.foreach]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Function>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+for_each(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Function __f)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    __pstl::__internal::__pattern_walk1(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last, __f);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Function>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+for_each_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _Size __n, _Function __f)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    return __pstl::__internal::__pattern_walk1_n(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __n,
+                                                 __f);
+}
+
+// [alg.find]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Predicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+find_if(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    return __pstl::__internal::__pattern_find_if(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                 __last, __pred);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Predicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+find_if_not(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
+{
+    return std::find_if(std::forward<_ExecutionPolicy>(__exec), __first, __last, std::not_fn(__pred));
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+find(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
+{
+    return std::find_if(std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                        __pstl::__internal::__equal_value<_Tp>(__value));
+}
+
+// [alg.find.end]
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator1>
+find_end(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __s_first,
+         _ForwardIterator2 __s_last, _BinaryPredicate __pred)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __s_first);
+
+    return __pstl::__internal::__pattern_find_end(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                  __last, __s_first, __s_last, __pred);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator1>
+find_end(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __s_first,
+         _ForwardIterator2 __s_last)
+{
+    return std::find_end(std::forward<_ExecutionPolicy>(__exec), __first, __last, __s_first, __s_last,
+                         std::equal_to<>());
+}
+
+// [alg.find_first_of]
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator1>
+find_first_of(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+              _ForwardIterator2 __s_first, _ForwardIterator2 __s_last, _BinaryPredicate __pred)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __s_first);
+
+    return __pstl::__internal::__pattern_find_first_of(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                       __last, __s_first, __s_last, __pred);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator1>
+find_first_of(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+              _ForwardIterator2 __s_first, _ForwardIterator2 __s_last)
+{
+    return std::find_first_of(std::forward<_ExecutionPolicy>(__exec), __first, __last, __s_first, __s_last,
+                              std::equal_to<>());
+}
+
+// [alg.adjacent_find]
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+adjacent_find(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType;
+    return __pstl::__internal::__pattern_adjacent_find(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                       __last, std::equal_to<_ValueType>(), /*first_semantic*/ false);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _BinaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+adjacent_find(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+    return __pstl::__internal::__pattern_adjacent_find(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                       __last, __pred, /*first_semantic*/ false);
+}
+
+// [alg.count]
+
+// Implementation note: count and count_if call the pattern directly instead of calling std::transform_reduce
+// so that we do not have to include <numeric>.
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy,
+                                                 typename iterator_traits<_ForwardIterator>::difference_type>
+count(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType;
+    return __pstl::__internal::__pattern_count(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                               [&__value](const _ValueType& __x) { return __value == __x; });
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Predicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy,
+                                                 typename iterator_traits<_ForwardIterator>::difference_type>
+count_if(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+    return __pstl::__internal::__pattern_count(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                               __pred);
+}
+
+// [alg.search]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator1>
+search(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __s_first,
+       _ForwardIterator2 __s_last, _BinaryPredicate __pred)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __s_first);
+
+    return __pstl::__internal::__pattern_search(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                                __s_first, __s_last, __pred);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator1>
+search(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __s_first,
+       _ForwardIterator2 __s_last)
+{
+    return std::search(std::forward<_ExecutionPolicy>(__exec), __first, __last, __s_first, __s_last, std::equal_to<>());
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Tp, class _BinaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+search_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Size __count,
+         const _Tp& __value, _BinaryPredicate __pred)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    return __pstl::__internal::__pattern_search_n(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                  __last, __count, __value, __pred);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+search_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Size __count,
+         const _Tp& __value)
+{
+    return std::search_n(std::forward<_ExecutionPolicy>(__exec), __first, __last, __count, __value,
+                         std::equal_to<typename iterator_traits<_ForwardIterator>::value_type>());
+}
+
+// [alg.copy]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+copy(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __result)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __result);
+
+    using __is_vector = typename decltype(__dispatch_tag)::__is_vector;
+
+    return __pstl::__internal::__pattern_walk2_brick(
+        __dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last, __result,
+        [](_ForwardIterator1 __begin, _ForwardIterator1 __end, _ForwardIterator2 __res)
+        { return __pstl::__internal::__brick_copy(__begin, __end, __res, __is_vector{}); });
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _Size, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+copy_n(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _Size __n, _ForwardIterator2 __result)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __result);
+
+    using __is_vector = typename decltype(__dispatch_tag)::__is_vector;
+
+    return __pstl::__internal::__pattern_walk2_brick_n(
+        __dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __n, __result,
+        [](_ForwardIterator1 __begin, _Size __sz, _ForwardIterator2 __res)
+        { return __pstl::__internal::__brick_copy_n(__begin, __sz, __res, __is_vector{}); });
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Predicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+copy_if(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __result,
+        _Predicate __pred)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __result);
+
+    return __pstl::__internal::__pattern_copy_if(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                 __last, __result, __pred);
+}
+
+// [alg.swap]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+swap_ranges(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+            _ForwardIterator2 __first2)
+{
+    typedef typename iterator_traits<_ForwardIterator1>::reference _ReferenceType1;
+    typedef typename iterator_traits<_ForwardIterator2>::reference _ReferenceType2;
+
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first1, __first2);
+
+    return __pstl::__internal::__pattern_walk2(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first1,
+                                               __last1, __first2,
+                                               [](_ReferenceType1 __x, _ReferenceType2 __y)
+                                               {
+                                                   using std::swap;
+                                                   swap(__x, __y);
+                                               });
+}
+
+// [alg.transform]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _UnaryOperation>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+transform(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __result,
+          _UnaryOperation __op)
+{
+    typedef typename iterator_traits<_ForwardIterator1>::reference _InputType;
+    typedef typename iterator_traits<_ForwardIterator2>::reference _OutputType;
+
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __result);
+
+    return __pstl::__internal::__pattern_walk2(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                               __result,
+                                               [__op](_InputType __x, _OutputType __y) mutable { __y = __op(__x); });
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator,
+          class _BinaryOperation>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+transform(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+          _ForwardIterator __result, _BinaryOperation __op)
+{
+    typedef typename iterator_traits<_ForwardIterator1>::reference _Input1Type;
+    typedef typename iterator_traits<_ForwardIterator2>::reference _Input2Type;
+    typedef typename iterator_traits<_ForwardIterator>::reference _OutputType;
+
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first1, __first2, __result);
+
+    return __pstl::__internal::__pattern_walk3(
+        __dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __first2, __result,
+        [__op](_Input1Type x, _Input2Type y, _OutputType z) mutable { z = __op(x, y); });
+}
+
+// [alg.replace]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _UnaryPredicate, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+replace_if(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _UnaryPredicate __pred,
+           const _Tp& __new_value)
+{
+    typedef typename iterator_traits<_ForwardIterator>::reference _ElementType;
+
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    __pstl::__internal::__pattern_walk1(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                        [&__pred, &__new_value](_ElementType __elem)
+                                        {
+                                            if (__pred(__elem))
+                                            {
+                                                __elem = __new_value;
+                                            }
+                                        });
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+replace(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __old_value,
+        const _Tp& __new_value)
+{
+    std::replace_if(std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                    __pstl::__internal::__equal_value<_Tp>(__old_value), __new_value);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _UnaryPredicate, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+replace_copy_if(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+                _ForwardIterator2 __result, _UnaryPredicate __pred, const _Tp& __new_value)
+{
+    typedef typename iterator_traits<_ForwardIterator1>::reference _InputType;
+    typedef typename iterator_traits<_ForwardIterator2>::reference _OutputType;
+
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __result);
+
+    return __pstl::__internal::__pattern_walk2(
+        __dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last, __result,
+        [__pred, &__new_value](_InputType __x, _OutputType __y) mutable { __y = __pred(__x) ? __new_value : __x; });
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+replace_copy(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __result,
+             const _Tp& __old_value, const _Tp& __new_value)
+{
+    return std::replace_copy_if(std::forward<_ExecutionPolicy>(__exec), __first, __last, __result,
+                                __pstl::__internal::__equal_value<_Tp>(__old_value), __new_value);
+}
+
+// [alg.fill]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+fill(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    __pstl::__internal::__pattern_fill(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                       __value);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+fill_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _Size __count, const _Tp& __value)
+{
+    if (__count <= 0)
+        return __first;
+
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    return __pstl::__internal::__pattern_fill_n(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                __count, __value);
+}
+
+// [alg.generate]
+template <class _ExecutionPolicy, class _ForwardIterator, class _Generator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+generate(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Generator __g)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    __pstl::__internal::__pattern_generate(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                           __g);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Generator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+generate_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _Size __count, _Generator __g)
+{
+    if (__count <= 0)
+        return __first;
+
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    return __pstl::__internal::__pattern_generate_n(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                    __count, __g);
+}
+
+// [alg.remove]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Predicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+remove_copy_if(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+               _ForwardIterator2 __result, _Predicate __pred)
+{
+    return std::copy_if(std::forward<_ExecutionPolicy>(__exec), __first, __last, __result, std::not_fn(__pred));
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+remove_copy(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __result,
+            const _Tp& __value)
+{
+    return std::copy_if(std::forward<_ExecutionPolicy>(__exec), __first, __last, __result,
+                        __pstl::__internal::__not_equal_value<_Tp>(__value));
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _UnaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+remove_if(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _UnaryPredicate __pred)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    return __pstl::__internal::__pattern_remove_if(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                   __last, __pred);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+remove(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
+{
+    return std::remove_if(std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                          __pstl::__internal::__equal_value<_Tp>(__value));
+}
+
+// [alg.unique]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _BinaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+unique(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    return __pstl::__internal::__pattern_unique(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                                __pred);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+unique(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last)
+{
+    return std::unique(std::forward<_ExecutionPolicy>(__exec), __first, __last, std::equal_to<>());
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+unique_copy(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __result,
+            _BinaryPredicate __pred)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __result);
+
+    return __pstl::__internal::__pattern_unique_copy(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                     __last, __result, __pred);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+unique_copy(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __result)
+{
+    return std::unique_copy(__exec, __first, __last, __result, std::equal_to<>());
+}
+
+// [alg.reverse]
+
+template <class _ExecutionPolicy, class _BidirectionalIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+reverse(_ExecutionPolicy&& __exec, _BidirectionalIterator __first, _BidirectionalIterator __last)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    __pstl::__internal::__pattern_reverse(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last);
+}
+
+template <class _ExecutionPolicy, class _BidirectionalIterator, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+reverse_copy(_ExecutionPolicy&& __exec, _BidirectionalIterator __first, _BidirectionalIterator __last,
+             _ForwardIterator __d_first)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __d_first);
+
+    return __pstl::__internal::__pattern_reverse_copy(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                      __last, __d_first);
+}
+
+// [alg.rotate]
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+rotate(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    return __pstl::__internal::__pattern_rotate(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                __middle, __last);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+rotate_copy(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __middle, _ForwardIterator1 __last,
+            _ForwardIterator2 __result)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __result);
+
+    return __pstl::__internal::__pattern_rotate_copy(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                     __middle, __last, __result);
+}
+
+// [alg.partitions]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _UnaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+is_partitioned(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _UnaryPredicate __pred)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+    return __pstl::__internal::__pattern_is_partitioned(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                        __last, __pred);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _UnaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+partition(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _UnaryPredicate __pred)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    return __pstl::__internal::__pattern_partition(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                   __last, __pred);
+}
+
+template <class _ExecutionPolicy, class _BidirectionalIterator, class _UnaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _BidirectionalIterator>
+stable_partition(_ExecutionPolicy&& __exec, _BidirectionalIterator __first, _BidirectionalIterator __last,
+                 _UnaryPredicate __pred)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+    return __pstl::__internal::__pattern_stable_partition(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec),
+                                                          __first, __last, __pred);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _ForwardIterator1, class _ForwardIterator2,
+          class _UnaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, std::pair<_ForwardIterator1, _ForwardIterator2>>
+partition_copy(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last,
+               _ForwardIterator1 __out_true, _ForwardIterator2 __out_false, _UnaryPredicate __pred)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __out_true, __out_false);
+
+    return __pstl::__internal::__pattern_partition_copy(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                        __last, __out_true, __out_false, __pred);
+}
+
+// [alg.sort]
+
+template <class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+sort(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type _InputType;
+    return __pstl::__internal::__pattern_sort(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                              __comp, typename std::is_move_constructible<_InputType>::type());
+}
+
+template <class _ExecutionPolicy, class _RandomAccessIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+sort(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    typedef typename std::iterator_traits<_RandomAccessIterator>::value_type _InputType;
+    std::sort(std::forward<_ExecutionPolicy>(__exec), __first, __last, std::less<_InputType>());
+}
+
+// [stable.sort]
+
+template <class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+stable_sort(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    return __pstl::__internal::__pattern_stable_sort(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                     __last, __comp);
+}
+
+template <class _ExecutionPolicy, class _RandomAccessIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+stable_sort(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    typedef typename std::iterator_traits<_RandomAccessIterator>::value_type _InputType;
+    std::stable_sort(__exec, __first, __last, std::less<_InputType>());
+}
+
+// [mismatch]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, std::pair<_ForwardIterator1, _ForwardIterator2>>
+mismatch(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+         _ForwardIterator2 __last2, _BinaryPredicate __pred)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first1, __first2);
+
+    return __pstl::__internal::__pattern_mismatch(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first1,
+                                                  __last1, __first2, __last2, __pred);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, std::pair<_ForwardIterator1, _ForwardIterator2>>
+mismatch(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+         _BinaryPredicate __pred)
+{
+    return std::mismatch(__exec, __first1, __last1, __first2, std::next(__first2, std::distance(__first1, __last1)),
+                         __pred);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, std::pair<_ForwardIterator1, _ForwardIterator2>>
+mismatch(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+         _ForwardIterator2 __last2)
+{
+    return std::mismatch(std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __first2, __last2,
+                         std::equal_to<>());
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, std::pair<_ForwardIterator1, _ForwardIterator2>>
+mismatch(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2)
+{
+    //TODO: to get rid of "distance"
+    return std::mismatch(std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __first2,
+                         std::next(__first2, std::distance(__first1, __last1)));
+}
+
+// [alg.equal]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+equal(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+      _BinaryPredicate __p)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first1, __first2);
+
+    return __pstl::__internal::__pattern_equal(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first1,
+                                               __last1, __first2, __p);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+equal(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2)
+{
+    return std::equal(std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __first2, std::equal_to<>());
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+equal(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+      _ForwardIterator2 __last2, _BinaryPredicate __p)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first1, __first2);
+
+    return __pstl::__internal::__pattern_equal(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first1,
+                                               __last1, __first2, __last2, __p);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+equal(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+      _ForwardIterator2 __last2)
+{
+    return equal(std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __first2, __last2, std::equal_to<>());
+}
+
+// [alg.move]
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+move(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __d_first)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __d_first);
+
+    using __is_vector = typename decltype(__dispatch_tag)::__is_vector;
+
+    return __pstl::__internal::__pattern_walk2_brick(
+        __dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last, __d_first,
+        [](_ForwardIterator1 __begin, _ForwardIterator1 __end, _ForwardIterator2 __res)
+        { return __pstl::__internal::__brick_move(__begin, __end, __res, __is_vector{}); });
+}
+
+// [partial.sort]
+
+template <class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+partial_sort(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __middle,
+             _RandomAccessIterator __last, _Compare __comp)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    __pstl::__internal::__pattern_partial_sort(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                               __middle, __last, __comp);
+}
+
+template <class _ExecutionPolicy, class _RandomAccessIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+partial_sort(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __middle,
+             _RandomAccessIterator __last)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type _InputType;
+    std::partial_sort(__exec, __first, __middle, __last, std::less<_InputType>());
+}
+
+// [partial.sort.copy]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _RandomAccessIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _RandomAccessIterator>
+partial_sort_copy(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last,
+                  _RandomAccessIterator __d_first, _RandomAccessIterator __d_last, _Compare __comp)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __d_first);
+
+    return __pstl::__internal::__pattern_partial_sort_copy(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec),
+                                                           __first, __last, __d_first, __d_last, __comp);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _RandomAccessIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _RandomAccessIterator>
+partial_sort_copy(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last,
+                  _RandomAccessIterator __d_first, _RandomAccessIterator __d_last)
+{
+    return std::partial_sort_copy(std::forward<_ExecutionPolicy>(__exec), __first, __last, __d_first, __d_last,
+                                  std::less<>());
+}
+
+// [is.sorted]
+template <class _ExecutionPolicy, class _ForwardIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+is_sorted_until(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+    const _ForwardIterator __res =
+        __pstl::__internal::__pattern_adjacent_find(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                    __last, __pstl::__internal::__reorder_pred<_Compare>(__comp),
+                                                    /*first_semantic*/ false);
+    return __res == __last ? __last : std::next(__res);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+is_sorted_until(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last)
+{
+    typedef typename std::iterator_traits<_ForwardIterator>::value_type _InputType;
+    return is_sorted_until(std::forward<_ExecutionPolicy>(__exec), __first, __last, std::less<_InputType>());
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+is_sorted(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+    return __pstl::__internal::__pattern_adjacent_find(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                       __last, __pstl::__internal::__reorder_pred<_Compare>(__comp),
+                                                       /*or_semantic*/ true) == __last;
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+is_sorted(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last)
+{
+    typedef typename std::iterator_traits<_ForwardIterator>::value_type _InputType;
+    return std::is_sorted(std::forward<_ExecutionPolicy>(__exec), __first, __last, std::less<_InputType>());
+}
+
+// [alg.merge]
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator,
+          class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+merge(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+      _ForwardIterator2 __last2, _ForwardIterator __d_first, _Compare __comp)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first1, __first2, __d_first);
+
+    return __pstl::__internal::__pattern_merge(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first1,
+                                               __last1, __first2, __last2, __d_first, __comp);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+merge(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+      _ForwardIterator2 __last2, _ForwardIterator __d_first)
+{
+    return std::merge(std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __first2, __last2, __d_first,
+                      std::less<>());
+}
+
+template <class _ExecutionPolicy, class _BidirectionalIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+inplace_merge(_ExecutionPolicy&& __exec, _BidirectionalIterator __first, _BidirectionalIterator __middle,
+              _BidirectionalIterator __last, _Compare __comp)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    __pstl::__internal::__pattern_inplace_merge(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                __middle, __last, __comp);
+}
+
+template <class _ExecutionPolicy, class _BidirectionalIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+inplace_merge(_ExecutionPolicy&& __exec, _BidirectionalIterator __first, _BidirectionalIterator __middle,
+              _BidirectionalIterator __last)
+{
+    typedef typename std::iterator_traits<_BidirectionalIterator>::value_type _InputType;
+    std::inplace_merge(__exec, __first, __middle, __last, std::less<_InputType>());
+}
+
+// [includes]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+includes(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+         _ForwardIterator2 __last2, _Compare __comp)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first1, __first2);
+
+    return __pstl::__internal::__pattern_includes(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first1,
+                                                  __last1, __first2, __last2, __comp);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+includes(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+         _ForwardIterator2 __last2)
+{
+    return std::includes(std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __first2, __last2, std::less<>());
+}
+
+// [set.union]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator,
+          class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+set_union(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+          _ForwardIterator2 __last2, _ForwardIterator __result, _Compare __comp)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first1, __first2, __result);
+
+    return __pstl::__internal::__pattern_set_union(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first1,
+                                                   __last1, __first2, __last2, __result, __comp);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+set_union(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+          _ForwardIterator2 __last2, _ForwardIterator __result)
+{
+    return std::set_union(std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __first2, __last2, __result,
+                          std::less<>());
+}
+
+// [set.intersection]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator,
+          class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+set_intersection(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                 _ForwardIterator2 __first2, _ForwardIterator2 __last2, _ForwardIterator __result, _Compare __comp)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first1, __first2, __result);
+
+    return __pstl::__internal::__pattern_set_intersection(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec),
+                                                          __first1, __last1, __first2, __last2, __result, __comp);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+set_intersection(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                 _ForwardIterator2 __first2, _ForwardIterator2 __last2, _ForwardIterator __result)
+{
+    return std::set_intersection(std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __first2, __last2, __result,
+                                 std::less<>());
+}
+
+// [set.difference]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator,
+          class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+set_difference(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+               _ForwardIterator2 __first2, _ForwardIterator2 __last2, _ForwardIterator __result, _Compare __comp)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first1, __first2, __result);
+
+    return __pstl::__internal::__pattern_set_difference(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec),
+                                                        __first1, __last1, __first2, __last2, __result, __comp);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+set_difference(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+               _ForwardIterator2 __first2, _ForwardIterator2 __last2, _ForwardIterator __result)
+{
+    return std::set_difference(std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __first2, __last2, __result,
+                               std::less<>());
+}
+
+// [set.symmetric.difference]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator,
+          class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+set_symmetric_difference(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                         _ForwardIterator2 __first2, _ForwardIterator2 __last2, _ForwardIterator __result,
+                         _Compare __comp)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first1, __first2, __result);
+
+    return __pstl::__internal::__pattern_set_symmetric_difference(
+        __dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __first2, __last2, __result, __comp);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+set_symmetric_difference(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                         _ForwardIterator2 __first2, _ForwardIterator2 __last2, _ForwardIterator __result)
+{
+    return std::set_symmetric_difference(std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __first2, __last2,
+                                         __result, std::less<>());
+}
+
+// [is.heap]
+template <class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _RandomAccessIterator>
+is_heap_until(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    return __pstl::__internal::__pattern_is_heap_until(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                       __last, __comp);
+}
+
+template <class _ExecutionPolicy, class _RandomAccessIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _RandomAccessIterator>
+is_heap_until(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    typedef typename std::iterator_traits<_RandomAccessIterator>::value_type _InputType;
+    return std::is_heap_until(std::forward<_ExecutionPolicy>(__exec), __first, __last, std::less<_InputType>());
+}
+
+template <class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+is_heap(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    return std::is_heap_until(std::forward<_ExecutionPolicy>(__exec), __first, __last, __comp) == __last;
+}
+
+template <class _ExecutionPolicy, class _RandomAccessIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+is_heap(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    typedef typename std::iterator_traits<_RandomAccessIterator>::value_type _InputType;
+    return std::is_heap(std::forward<_ExecutionPolicy>(__exec), __first, __last, std::less<_InputType>());
+}
+
+// [alg.min.max]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+min_element(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+    return __pstl::__internal::__pattern_min_element(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                     __last, __comp);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+min_element(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last)
+{
+    typedef typename std::iterator_traits<_ForwardIterator>::value_type _InputType;
+    return std::min_element(std::forward<_ExecutionPolicy>(__exec), __first, __last, std::less<_InputType>());
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+max_element(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
+{
+    return min_element(std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                       __pstl::__internal::__reorder_pred<_Compare>(__comp));
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+max_element(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last)
+{
+    typedef typename std::iterator_traits<_ForwardIterator>::value_type _InputType;
+    return std::min_element(std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                            __pstl::__internal::__reorder_pred<std::less<_InputType>>(std::less<_InputType>()));
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, std::pair<_ForwardIterator, _ForwardIterator>>
+minmax_element(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+    return __pstl::__internal::__pattern_minmax_element(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                        __last, __comp);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, std::pair<_ForwardIterator, _ForwardIterator>>
+minmax_element(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last)
+{
+    typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType;
+    return std::minmax_element(std::forward<_ExecutionPolicy>(__exec), __first, __last, std::less<_ValueType>());
+}
+
+// [alg.nth.element]
+
+template <class _ExecutionPolicy, class _RandomAccessIterator, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+nth_element(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __nth,
+            _RandomAccessIterator __last, _Compare __comp)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    __pstl::__internal::__pattern_nth_element(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __nth,
+                                              __last, __comp);
+}
+
+template <class _ExecutionPolicy, class _RandomAccessIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+nth_element(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __nth,
+            _RandomAccessIterator __last)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type _InputType;
+    std::nth_element(std::forward<_ExecutionPolicy>(__exec), __first, __nth, __last, std::less<_InputType>());
+}
+
+// [alg.lex.comparison]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Compare>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+lexicographical_compare(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                        _ForwardIterator2 __first2, _ForwardIterator2 __last2, _Compare __comp)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first1, __first2);
+
+    return __pstl::__internal::__pattern_lexicographical_compare(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec),
+                                                                 __first1, __last1, __first2, __last2, __comp);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, bool>
+lexicographical_compare(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                        _ForwardIterator2 __first2, _ForwardIterator2 __last2)
+{
+    return std::lexicographical_compare(std::forward<_ExecutionPolicy>(__exec), __first1, __last1, __first2, __last2,
+                                        std::less<>());
+}
+
+} // namespace std
+
+_PSTL_HIDE_FROM_ABI_POP
+
+#endif /* _PSTL_GLUE_ALGORITHM_IMPL_H */
diff --git a/pstl/include/pstl/internal/glue_execution_defs.h b/pstl/include/pstl/internal/glue_execution_defs.h
new file mode 100644
index 0000000..df9a477
--- /dev/null
+++ b/pstl/include/pstl/internal/glue_execution_defs.h
@@ -0,0 +1,55 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_GLUE_EXECUTION_DEFS_H
+#define _PSTL_GLUE_EXECUTION_DEFS_H
+
+#include <type_traits>
+
+#include "execution_defs.h"
+#include "pstl_config.h"
+
+namespace std
+{
+// Type trait
+using __pstl::execution::is_execution_policy;
+#if defined(_PSTL_CPP14_VARIABLE_TEMPLATES_PRESENT)
+#    if defined(__INTEL_COMPILER)
+template <class T>
+constexpr bool is_execution_policy_v = is_execution_policy<T>::value;
+#    else
+using __pstl::execution::is_execution_policy_v;
+#    endif
+#endif
+
+namespace execution
+{
+// Standard C++ policy classes
+using __pstl::execution::parallel_policy;
+using __pstl::execution::parallel_unsequenced_policy;
+using __pstl::execution::sequenced_policy;
+
+// Standard predefined policy instances
+using __pstl::execution::par;
+using __pstl::execution::par_unseq;
+using __pstl::execution::seq;
+
+// Implementation-defined names
+// Unsequenced policy is not yet standard, but for consistency
+// we include it into namespace std::execution as well
+using __pstl::execution::unseq;
+using __pstl::execution::unsequenced_policy;
+} // namespace execution
+} // namespace std
+
+#include "algorithm_impl.h"
+#include "numeric_impl.h"
+#include "parallel_backend.h"
+
+#endif /* _PSTL_GLUE_EXECUTION_DEFS_H */
diff --git a/pstl/include/pstl/internal/glue_memory_defs.h b/pstl/include/pstl/internal/glue_memory_defs.h
new file mode 100644
index 0000000..ae52333
--- /dev/null
+++ b/pstl/include/pstl/internal/glue_memory_defs.h
@@ -0,0 +1,85 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_GLUE_MEMORY_DEFS_H
+#define _PSTL_GLUE_MEMORY_DEFS_H
+
+#include "execution_defs.h"
+#include "pstl_config.h"
+
+_PSTL_HIDE_FROM_ABI_PUSH
+
+namespace std
+{
+
+// [uninitialized.copy]
+
+template <class _ExecutionPolicy, class _InputIterator, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+uninitialized_copy(_ExecutionPolicy&& __exec, _InputIterator __first, _InputIterator __last, _ForwardIterator __result);
+
+template <class _ExecutionPolicy, class _InputIterator, class _Size, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+uninitialized_copy_n(_ExecutionPolicy&& __exec, _InputIterator __first, _Size __n, _ForwardIterator __result);
+
+// [uninitialized.move]
+
+template <class _ExecutionPolicy, class _InputIterator, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+uninitialized_move(_ExecutionPolicy&& __exec, _InputIterator __first, _InputIterator __last, _ForwardIterator __result);
+
+template <class _ExecutionPolicy, class _InputIterator, class _Size, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+uninitialized_move_n(_ExecutionPolicy&& __exec, _InputIterator __first, _Size __n, _ForwardIterator __result);
+
+// [uninitialized.fill]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+uninitialized_fill(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+uninitialized_fill_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _Size __n, const _Tp& __value);
+
+// [specialized.destroy]
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+destroy(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Size>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+destroy_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _Size __n);
+
+// [uninitialized.construct.default]
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+uninitialized_default_construct(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Size>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+uninitialized_default_construct_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _Size __n);
+
+// [uninitialized.construct.value]
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+uninitialized_value_construct(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Size>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+uninitialized_value_construct_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _Size __n);
+
+} //  namespace std
+
+_PSTL_HIDE_FROM_ABI_POP
+
+#endif /* _PSTL_GLUE_MEMORY_DEFS_H */
diff --git a/pstl/include/pstl/internal/glue_memory_impl.h b/pstl/include/pstl/internal/glue_memory_impl.h
new file mode 100644
index 0000000..39c595d
--- /dev/null
+++ b/pstl/include/pstl/internal/glue_memory_impl.h
@@ -0,0 +1,352 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_GLUE_MEMORY_IMPL_H
+#define _PSTL_GLUE_MEMORY_IMPL_H
+
+#include "pstl_config.h"
+
+#include "execution_defs.h"
+#include "utils.h"
+#include "algorithm_fwd.h"
+
+#include "execution_impl.h"
+
+_PSTL_HIDE_FROM_ABI_PUSH
+
+namespace std
+{
+
+// [uninitialized.copy]
+
+template <class _ExecutionPolicy, class _InputIterator, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+uninitialized_copy(_ExecutionPolicy&& __exec, _InputIterator __first, _InputIterator __last, _ForwardIterator __result)
+{
+    typedef typename iterator_traits<_InputIterator>::value_type _ValueType1;
+    typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType2;
+    typedef typename iterator_traits<_InputIterator>::reference _ReferenceType1;
+    typedef typename iterator_traits<_ForwardIterator>::reference _ReferenceType2;
+
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __result);
+
+    using __is_vector = typename decltype(__dispatch_tag)::__is_vector;
+
+    return __pstl::__internal::__invoke_if_else(
+        std::integral_constant < bool, std::is_trivial<_ValueType1>::value&& std::is_trivial<_ValueType2>::value > (),
+        [&]()
+        {
+            return __pstl::__internal::__pattern_walk2_brick(
+                __dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last, __result,
+                [](_InputIterator __begin, _InputIterator __end, _ForwardIterator __res)
+                { return __pstl::__internal::__brick_copy(__begin, __end, __res, __is_vector{}); });
+        },
+        [&]()
+        {
+            return __pstl::__internal::__pattern_walk2(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                       __last, __result,
+                                                       [](_ReferenceType1 __val1, _ReferenceType2 __val2)
+                                                       { ::new (std::addressof(__val2)) _ValueType2(__val1); });
+        });
+}
+
+template <class _ExecutionPolicy, class _InputIterator, class _Size, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+uninitialized_copy_n(_ExecutionPolicy&& __exec, _InputIterator __first, _Size __n, _ForwardIterator __result)
+{
+    typedef typename iterator_traits<_InputIterator>::value_type _ValueType1;
+    typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType2;
+    typedef typename iterator_traits<_InputIterator>::reference _ReferenceType1;
+    typedef typename iterator_traits<_ForwardIterator>::reference _ReferenceType2;
+
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __result);
+
+    using __is_vector = typename decltype(__dispatch_tag)::__is_vector;
+
+    return __pstl::__internal::__invoke_if_else(
+        std::integral_constant < bool, std::is_trivial<_ValueType1>::value&& std::is_trivial<_ValueType2>::value > (),
+        [&]()
+        {
+            return __pstl::__internal::__pattern_walk2_brick_n(
+                __dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __n, __result,
+                [](_InputIterator __begin, _Size __sz, _ForwardIterator __res)
+                { return __pstl::__internal::__brick_copy_n(__begin, __sz, __res, __is_vector{}); });
+        },
+        [&]()
+        {
+            return __pstl::__internal::__pattern_walk2_n(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec),
+                                                         __first, __n, __result,
+                                                         [](_ReferenceType1 __val1, _ReferenceType2 __val2)
+                                                         { ::new (std::addressof(__val2)) _ValueType2(__val1); });
+        });
+}
+
+// [uninitialized.move]
+
+template <class _ExecutionPolicy, class _InputIterator, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+uninitialized_move(_ExecutionPolicy&& __exec, _InputIterator __first, _InputIterator __last, _ForwardIterator __result)
+{
+    typedef typename iterator_traits<_InputIterator>::value_type _ValueType1;
+    typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType2;
+    typedef typename iterator_traits<_InputIterator>::reference _ReferenceType1;
+    typedef typename iterator_traits<_ForwardIterator>::reference _ReferenceType2;
+
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __result);
+
+    using __is_vector = typename decltype(__dispatch_tag)::__is_vector;
+
+    return __pstl::__internal::__invoke_if_else(
+        std::integral_constant < bool, std::is_trivial<_ValueType1>::value&& std::is_trivial<_ValueType2>::value > (),
+        [&]()
+        {
+            return __pstl::__internal::__pattern_walk2_brick(
+                __dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last, __result,
+                [](_InputIterator __begin, _InputIterator __end, _ForwardIterator __res)
+                { return __pstl::__internal::__brick_copy(__begin, __end, __res, __is_vector{}); });
+        },
+        [&]()
+        {
+            return __pstl::__internal::__pattern_walk2(
+                __dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last, __result,
+                [](_ReferenceType1 __val1, _ReferenceType2 __val2)
+                { ::new (std::addressof(__val2)) _ValueType2(std::move(__val1)); });
+        });
+}
+
+template <class _ExecutionPolicy, class _InputIterator, class _Size, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+uninitialized_move_n(_ExecutionPolicy&& __exec, _InputIterator __first, _Size __n, _ForwardIterator __result)
+{
+    typedef typename iterator_traits<_InputIterator>::value_type _ValueType1;
+    typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType2;
+    typedef typename iterator_traits<_InputIterator>::reference _ReferenceType1;
+    typedef typename iterator_traits<_ForwardIterator>::reference _ReferenceType2;
+
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __result);
+
+    using __is_vector = typename decltype(__dispatch_tag)::__is_vector;
+
+    return __pstl::__internal::__invoke_if_else(
+        std::integral_constant < bool, std::is_trivial<_ValueType1>::value&& std::is_trivial<_ValueType2>::value > (),
+        [&]()
+        {
+            return __pstl::__internal::__pattern_walk2_brick_n(
+                __dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __n, __result,
+                [](_InputIterator __begin, _Size __sz, _ForwardIterator __res)
+                { return __pstl::__internal::__brick_copy_n(__begin, __sz, __res, __is_vector{}); });
+        },
+        [&]()
+        {
+            return __pstl::__internal::__pattern_walk2_n(
+                __dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __n, __result,
+                [](_ReferenceType1 __val1, _ReferenceType2 __val2)
+                { ::new (std::addressof(__val2)) _ValueType2(std::move(__val1)); });
+        });
+}
+
+// [uninitialized.fill]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+uninitialized_fill(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
+{
+    typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType;
+    typedef typename iterator_traits<_ForwardIterator>::reference _ReferenceType;
+
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    using __is_vector = typename decltype(__dispatch_tag)::__is_vector;
+
+    __pstl::__internal::__invoke_if_else(
+        std::is_arithmetic<_ValueType>(),
+        [&]()
+        {
+            __pstl::__internal::__pattern_walk_brick(
+                __dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                [&__value](_ForwardIterator __begin, _ForwardIterator __end)
+                { __pstl::__internal::__brick_fill(__begin, __end, _ValueType(__value), __is_vector{}); });
+        },
+        [&]()
+        {
+            __pstl::__internal::__pattern_walk1(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                                [&__value](_ReferenceType __val)
+                                                { ::new (std::addressof(__val)) _ValueType(__value); });
+        });
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Size, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+uninitialized_fill_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _Size __n, const _Tp& __value)
+{
+    typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType;
+    typedef typename iterator_traits<_ForwardIterator>::reference _ReferenceType;
+
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    using __is_vector = typename decltype(__dispatch_tag)::__is_vector;
+
+    return __pstl::__internal::__invoke_if_else(
+        std::is_arithmetic<_ValueType>(),
+        [&]()
+        {
+            return __pstl::__internal::__pattern_walk_brick_n(
+                __dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __n,
+                [&__value](_ForwardIterator __begin, _Size __count)
+                { return __pstl::__internal::__brick_fill_n(__begin, __count, _ValueType(__value), __is_vector{}); });
+        },
+        [&]()
+        {
+            return __pstl::__internal::__pattern_walk1_n(
+                __dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __n,
+                [&__value](_ReferenceType __val) { ::new (std::addressof(__val)) _ValueType(__value); });
+        });
+}
+
+// [specialized.destroy]
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+destroy(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last)
+{
+    typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType;
+    typedef typename iterator_traits<_ForwardIterator>::reference _ReferenceType;
+
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    __pstl::__internal::__invoke_if_not(std::is_trivially_destructible<_ValueType>(),
+                                        [&]()
+                                        {
+                                            __pstl::__internal::__pattern_walk1(
+                                                __dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                                [](_ReferenceType __val) { __val.~_ValueType(); });
+                                        });
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Size>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+destroy_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _Size __n)
+{
+    typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType;
+    typedef typename iterator_traits<_ForwardIterator>::reference _ReferenceType;
+
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    return __pstl::__internal::__invoke_if_else(
+        std::is_trivially_destructible<_ValueType>(), [&]() { return std::next(__first, __n); },
+        [&]()
+        {
+            return __pstl::__internal::__pattern_walk1_n(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec),
+                                                         __first, __n,
+                                                         [](_ReferenceType __val) { __val.~_ValueType(); });
+        });
+}
+
+// [uninitialized.construct.default]
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+uninitialized_default_construct(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last)
+{
+    typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType;
+    typedef typename iterator_traits<_ForwardIterator>::reference _ReferenceType;
+
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    __pstl::__internal::__invoke_if_not(std::is_trivial<_ValueType>(),
+                                        [&]()
+                                        {
+                                            __pstl::__internal::__pattern_walk1(
+                                                __dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                                [](_ReferenceType __val) { ::new (std::addressof(__val)) _ValueType; });
+                                        });
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Size>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+uninitialized_default_construct_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _Size __n)
+{
+    typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType;
+    typedef typename iterator_traits<_ForwardIterator>::reference _ReferenceType;
+
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    return __pstl::__internal::__invoke_if_else(
+        std::is_trivial<_ValueType>(), [&]() { return std::next(__first, __n); },
+        [&]()
+        {
+            return __pstl::__internal::__pattern_walk1_n(
+                __dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __n,
+                [](_ReferenceType __val) { ::new (std::addressof(__val)) _ValueType; });
+        });
+}
+
+// [uninitialized.construct.value]
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, void>
+uninitialized_value_construct(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last)
+{
+    typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType;
+    typedef typename iterator_traits<_ForwardIterator>::reference _ReferenceType;
+
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    using __is_vector = typename decltype(__dispatch_tag)::__is_vector;
+
+    __pstl::__internal::__invoke_if_else(
+        std::is_trivial<_ValueType>(),
+        [&]()
+        {
+            __pstl::__internal::__pattern_walk_brick(
+                __dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                [](_ForwardIterator __begin, _ForwardIterator __end)
+                { __pstl::__internal::__brick_fill(__begin, __end, _ValueType(), __is_vector{}); });
+        },
+        [&]()
+        {
+            __pstl::__internal::__pattern_walk1(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                                [](_ReferenceType __val)
+                                                { ::new (std::addressof(__val)) _ValueType(); });
+        });
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Size>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator>
+uninitialized_value_construct_n(_ExecutionPolicy&& __exec, _ForwardIterator __first, _Size __n)
+{
+    typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType;
+    typedef typename iterator_traits<_ForwardIterator>::reference _ReferenceType;
+
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+
+    using __is_vector = typename decltype(__dispatch_tag)::__is_vector;
+
+    return __pstl::__internal::__invoke_if_else(
+        std::is_trivial<_ValueType>(),
+        [&]()
+        {
+            return __pstl::__internal::__pattern_walk_brick_n(
+                __dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __n,
+                [](_ForwardIterator __begin, _Size __count)
+                { return __pstl::__internal::__brick_fill_n(__begin, __count, _ValueType(), __is_vector{}); });
+        },
+        [&]()
+        {
+            return __pstl::__internal::__pattern_walk1_n(
+                __dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __n,
+                [](_ReferenceType __val) { ::new (std::addressof(__val)) _ValueType(); });
+        });
+}
+
+} // namespace std
+
+_PSTL_HIDE_FROM_ABI_POP
+
+#endif /* _PSTL_GLUE_MEMORY_IMPL_H */
diff --git a/pstl/include/pstl/internal/glue_numeric_defs.h b/pstl/include/pstl/internal/glue_numeric_defs.h
new file mode 100644
index 0000000..86cd38b
--- /dev/null
+++ b/pstl/include/pstl/internal/glue_numeric_defs.h
@@ -0,0 +1,124 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_GLUE_NUMERIC_DEFS_H
+#define _PSTL_GLUE_NUMERIC_DEFS_H
+
+#include <iterator>
+
+#include "execution_defs.h"
+#include "pstl_config.h"
+
+_PSTL_HIDE_FROM_ABI_PUSH
+
+namespace std
+{
+// [reduce]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Tp, class _BinaryOperation>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _Tp>
+reduce(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Tp __init,
+       _BinaryOperation __binary_op);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _Tp>
+reduce(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Tp __init);
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy,
+                                                 typename iterator_traits<_ForwardIterator>::value_type>
+reduce(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _Tp>
+transform_reduce(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                 _ForwardIterator2 __first2, _Tp __init);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Tp, class _BinaryOperation1,
+          class _BinaryOperation2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _Tp>
+transform_reduce(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                 _ForwardIterator2 __first2, _Tp __init, _BinaryOperation1 __binary_op1,
+                 _BinaryOperation2 __binary_op2);
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Tp, class _BinaryOperation, class _UnaryOperation>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _Tp>
+transform_reduce(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Tp __init,
+                 _BinaryOperation __binary_op, _UnaryOperation __unary_op);
+
+// [exclusive.scan]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+exclusive_scan(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+               _ForwardIterator2 __result, _Tp __init);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Tp, class _BinaryOperation>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+exclusive_scan(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+               _ForwardIterator2 __result, _Tp __init, _BinaryOperation __binary_op);
+
+// [inclusive.scan]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+inclusive_scan(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+               _ForwardIterator2 __result);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryOperation>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+inclusive_scan(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+               _ForwardIterator2 __result, _BinaryOperation __binary_op);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Tp, class _BinaryOperation>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+inclusive_scan(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+               _ForwardIterator2 __result, _BinaryOperation __binary_op, _Tp __init);
+
+// [transform.exclusive.scan]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Tp, class _BinaryOperation,
+          class _UnaryOperation>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+transform_exclusive_scan(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+                         _ForwardIterator2 __result, _Tp __init, _BinaryOperation __binary_op,
+                         _UnaryOperation __unary_op);
+
+// [transform.inclusive.scan]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryOperation,
+          class _UnaryOperation, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+transform_inclusive_scan(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+                         _ForwardIterator2 __result, _BinaryOperation __binary_op, _UnaryOperation __unary_op,
+                         _Tp __init);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _UnaryOperation,
+          class _BinaryOperation>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+transform_inclusive_scan(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+                         _ForwardIterator2 __result, _BinaryOperation __binary_op, _UnaryOperation __unary_op);
+
+// [adjacent.difference]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryOperation>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+adjacent_difference(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+                    _ForwardIterator2 __d_first, _BinaryOperation op);
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+adjacent_difference(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+                    _ForwardIterator2 __d_first);
+
+} // namespace std
+
+_PSTL_HIDE_FROM_ABI_POP
+
+#endif /* _PSTL_GLUE_NUMERIC_DEFS_H */
diff --git a/pstl/include/pstl/internal/glue_numeric_impl.h b/pstl/include/pstl/internal/glue_numeric_impl.h
new file mode 100644
index 0000000..ad268b5
--- /dev/null
+++ b/pstl/include/pstl/internal/glue_numeric_impl.h
@@ -0,0 +1,232 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_GLUE_NUMERIC_IMPL_H
+#define _PSTL_GLUE_NUMERIC_IMPL_H
+
+#include <functional>
+
+#include "pstl_config.h"
+
+#include "utils.h"
+#include "numeric_fwd.h"
+#include "execution_impl.h"
+
+_PSTL_HIDE_FROM_ABI_PUSH
+
+namespace std
+{
+
+// [reduce]
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Tp, class _BinaryOperation>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _Tp>
+reduce(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Tp __init,
+       _BinaryOperation __binary_op)
+{
+    return transform_reduce(std::forward<_ExecutionPolicy>(__exec), __first, __last, __init, __binary_op,
+                            __pstl::__internal::__no_op());
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _Tp>
+reduce(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Tp __init)
+{
+    return transform_reduce(std::forward<_ExecutionPolicy>(__exec), __first, __last, __init, std::plus<_Tp>(),
+                            __pstl::__internal::__no_op());
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy,
+                                                 typename iterator_traits<_ForwardIterator>::value_type>
+reduce(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last)
+{
+    typedef typename iterator_traits<_ForwardIterator>::value_type _ValueType;
+    return transform_reduce(std::forward<_ExecutionPolicy>(__exec), __first, __last, _ValueType{},
+                            std::plus<_ValueType>(), __pstl::__internal::__no_op());
+}
+
+// [transform.reduce]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _Tp>
+transform_reduce(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                 _ForwardIterator2 __first2, _Tp __init)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first1, __first2);
+
+    typedef typename iterator_traits<_ForwardIterator1>::value_type _InputType;
+    return __pstl::__internal::__pattern_transform_reduce(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec),
+                                                          __first1, __last1, __first2, __init, std::plus<_InputType>(),
+                                                          std::multiplies<_InputType>());
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Tp, class _BinaryOperation1,
+          class _BinaryOperation2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _Tp>
+transform_reduce(_ExecutionPolicy&& __exec, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                 _ForwardIterator2 __first2, _Tp __init, _BinaryOperation1 __binary_op1, _BinaryOperation2 __binary_op2)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first1, __first2);
+    return __pstl::__internal::__pattern_transform_reduce(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec),
+                                                          __first1, __last1, __first2, __init, __binary_op1,
+                                                          __binary_op2);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Tp, class _BinaryOperation, class _UnaryOperation>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _Tp>
+transform_reduce(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _Tp __init,
+                 _BinaryOperation __binary_op, _UnaryOperation __unary_op)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first);
+    return __pstl::__internal::__pattern_transform_reduce(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec),
+                                                          __first, __last, __init, __binary_op, __unary_op);
+}
+
+// [exclusive.scan]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+exclusive_scan(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+               _ForwardIterator2 __result, _Tp __init)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __result);
+
+    using namespace __pstl;
+    return __internal::__pattern_transform_scan(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                                __result, __pstl::__internal::__no_op(), __init, std::plus<_Tp>(),
+                                                /*inclusive=*/std::false_type());
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Tp, class _BinaryOperation>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+exclusive_scan(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+               _ForwardIterator2 __result, _Tp __init, _BinaryOperation __binary_op)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __result);
+
+    using namespace __pstl;
+    return __internal::__pattern_transform_scan(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                                __result, __pstl::__internal::__no_op(), __init, __binary_op,
+                                                /*inclusive=*/std::false_type());
+}
+
+// [inclusive.scan]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+inclusive_scan(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+               _ForwardIterator2 __result)
+{
+    typedef typename iterator_traits<_ForwardIterator1>::value_type _InputType;
+    return transform_inclusive_scan(std::forward<_ExecutionPolicy>(__exec), __first, __last, __result,
+                                    std::plus<_InputType>(), __pstl::__internal::__no_op());
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryOperation>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+inclusive_scan(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+               _ForwardIterator2 __result, _BinaryOperation __binary_op)
+{
+    return transform_inclusive_scan(std::forward<_ExecutionPolicy>(__exec), __first, __last, __result, __binary_op,
+                                    __pstl::__internal::__no_op());
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Tp, class _BinaryOperation>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+inclusive_scan(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+               _ForwardIterator2 __result, _BinaryOperation __binary_op, _Tp __init)
+{
+    return transform_inclusive_scan(std::forward<_ExecutionPolicy>(__exec), __first, __last, __result, __binary_op,
+                                    __pstl::__internal::__no_op(), __init);
+}
+
+// [transform.exclusive.scan]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Tp, class _BinaryOperation,
+          class _UnaryOperation>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+transform_exclusive_scan(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+                         _ForwardIterator2 __result, _Tp __init, _BinaryOperation __binary_op,
+                         _UnaryOperation __unary_op)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __result);
+
+    return __pstl::__internal::__pattern_transform_scan(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                        __last, __result, __unary_op, __init, __binary_op,
+                                                        /*inclusive=*/std::false_type());
+}
+
+// [transform.inclusive.scan]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryOperation,
+          class _UnaryOperation, class _Tp>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+transform_inclusive_scan(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+                         _ForwardIterator2 __result, _BinaryOperation __binary_op, _UnaryOperation __unary_op,
+                         _Tp __init)
+{
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __result);
+
+    return __pstl::__internal::__pattern_transform_scan(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec), __first,
+                                                        __last, __result, __unary_op, __init, __binary_op,
+                                                        /*inclusive=*/std::true_type());
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _UnaryOperation,
+          class _BinaryOperation>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+transform_inclusive_scan(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+                         _ForwardIterator2 __result, _BinaryOperation __binary_op, _UnaryOperation __unary_op)
+{
+    if (__first != __last)
+    {
+        auto __tmp = __unary_op(*__first);
+        *__result = __tmp;
+        return transform_inclusive_scan(std::forward<_ExecutionPolicy>(__exec), ++__first, __last, ++__result,
+                                        __binary_op, __unary_op, __tmp);
+    }
+    else
+    {
+        return __result;
+    }
+}
+
+// [adjacent.difference]
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _BinaryOperation>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+adjacent_difference(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+                    _ForwardIterator2 __d_first, _BinaryOperation __op)
+{
+
+    if (__first == __last)
+        return __d_first;
+
+    auto __dispatch_tag = __pstl::__internal::__select_backend(__exec, __first, __d_first);
+
+    return __pstl::__internal::__pattern_adjacent_difference(__dispatch_tag, std::forward<_ExecutionPolicy>(__exec),
+                                                             __first, __last, __d_first, __op);
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2>
+__pstl::__internal::__enable_if_execution_policy<_ExecutionPolicy, _ForwardIterator2>
+adjacent_difference(_ExecutionPolicy&& __exec, _ForwardIterator1 __first, _ForwardIterator1 __last,
+                    _ForwardIterator2 __d_first)
+{
+    typedef typename iterator_traits<_ForwardIterator1>::value_type _ValueType;
+    return adjacent_difference(std::forward<_ExecutionPolicy>(__exec), __first, __last, __d_first,
+                               std::minus<_ValueType>());
+}
+
+} // namespace std
+
+_PSTL_HIDE_FROM_ABI_POP
+
+#endif /* _PSTL_GLUE_NUMERIC_IMPL_H_ */
diff --git a/pstl/include/pstl/internal/memory_impl.h b/pstl/include/pstl/internal/memory_impl.h
new file mode 100644
index 0000000..942a30e
--- /dev/null
+++ b/pstl/include/pstl/internal/memory_impl.h
@@ -0,0 +1,112 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_MEMORY_IMPL_H
+#define _PSTL_MEMORY_IMPL_H
+
+#include <iterator>
+
+#include "pstl_config.h"
+#include "unseq_backend_simd.h"
+
+_PSTL_HIDE_FROM_ABI_PUSH
+
+namespace __pstl
+{
+namespace __internal
+{
+
+//------------------------------------------------------------------------
+// uninitialized_move
+//------------------------------------------------------------------------
+
+template <typename _ForwardIterator, typename _OutputIterator>
+_OutputIterator
+__brick_uninitialized_move(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator __result,
+                           /*vector=*/std::false_type) noexcept
+{
+    using _ValueType = typename std::iterator_traits<_OutputIterator>::value_type;
+    for (; __first != __last; ++__first, ++__result)
+    {
+        ::new (std::addressof(*__result)) _ValueType(std::move(*__first));
+    }
+    return __result;
+}
+
+template <typename _RandomAccessIterator, typename _OutputIterator>
+_OutputIterator
+__brick_uninitialized_move(_RandomAccessIterator __first, _RandomAccessIterator __last, _OutputIterator __result,
+                           /*vector=*/std::true_type) noexcept
+{
+    using __ValueType = typename std::iterator_traits<_OutputIterator>::value_type;
+    using _ReferenceType1 = typename std::iterator_traits<_RandomAccessIterator>::reference;
+    using _ReferenceType2 = typename std::iterator_traits<_OutputIterator>::reference;
+
+    return __unseq_backend::__simd_walk_2(
+        __first, __last - __first, __result,
+        [](_ReferenceType1 __x, _ReferenceType2 __y) { ::new (std::addressof(__y)) __ValueType(std::move(__x)); });
+}
+
+template <typename _Iterator>
+void
+__brick_destroy(_Iterator __first, _Iterator __last, /*vector*/ std::false_type) noexcept
+{
+    using _ValueType = typename std::iterator_traits<_Iterator>::value_type;
+
+    for (; __first != __last; ++__first)
+        __first->~_ValueType();
+}
+
+template <typename _RandomAccessIterator>
+void
+__brick_destroy(_RandomAccessIterator __first, _RandomAccessIterator __last, /*vector*/ std::true_type) noexcept
+{
+    using _ValueType = typename std::iterator_traits<_RandomAccessIterator>::value_type;
+    using _ReferenceType = typename std::iterator_traits<_RandomAccessIterator>::reference;
+
+    __unseq_backend::__simd_walk_1(__first, __last - __first, [](_ReferenceType __x) { __x.~_ValueType(); });
+}
+
+//------------------------------------------------------------------------
+// uninitialized copy
+//------------------------------------------------------------------------
+
+template <typename _ForwardIterator, typename _OutputIterator>
+_OutputIterator
+__brick_uninitialized_copy(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator __result,
+                           /*vector=*/std::false_type) noexcept
+{
+    using _ValueType = typename std::iterator_traits<_OutputIterator>::value_type;
+    for (; __first != __last; ++__first, ++__result)
+    {
+        ::new (std::addressof(*__result)) _ValueType(*__first);
+    }
+    return __result;
+}
+
+template <typename _RandomAccessIterator, typename _OutputIterator>
+_OutputIterator
+__brick_uninitialized_copy(_RandomAccessIterator __first, _RandomAccessIterator __last, _OutputIterator __result,
+                           /*vector=*/std::true_type) noexcept
+{
+    using __ValueType = typename std::iterator_traits<_OutputIterator>::value_type;
+    using _ReferenceType1 = typename std::iterator_traits<_RandomAccessIterator>::reference;
+    using _ReferenceType2 = typename std::iterator_traits<_OutputIterator>::reference;
+
+    return __unseq_backend::__simd_walk_2(
+        __first, __last - __first, __result,
+        [](_ReferenceType1 __x, _ReferenceType2 __y) { ::new (std::addressof(__y)) __ValueType(__x); });
+}
+
+} // namespace __internal
+} // namespace __pstl
+
+_PSTL_HIDE_FROM_ABI_POP
+
+#endif /* _PSTL_MEMORY_IMPL_H */
diff --git a/pstl/include/pstl/internal/numeric_fwd.h b/pstl/include/pstl/internal/numeric_fwd.h
new file mode 100644
index 0000000..7f7845b
--- /dev/null
+++ b/pstl/include/pstl/internal/numeric_fwd.h
@@ -0,0 +1,139 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_NUMERIC_FWD_H
+#define _PSTL_NUMERIC_FWD_H
+
+#include <type_traits>
+#include <utility>
+
+#include "pstl_config.h"
+
+_PSTL_HIDE_FROM_ABI_PUSH
+
+namespace __pstl
+{
+namespace __internal
+{
+
+//------------------------------------------------------------------------
+// transform_reduce (version with two binary functions, according to draft N4659)
+//------------------------------------------------------------------------
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _Tp, class _BinaryOperation1,
+          class _BinaryOperation2>
+_Tp __brick_transform_reduce(_RandomAccessIterator1, _RandomAccessIterator1, _RandomAccessIterator2, _Tp,
+                             _BinaryOperation1, _BinaryOperation2,
+                             /*__is_vector=*/std::true_type) noexcept;
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _Tp, class _BinaryOperation1, class _BinaryOperation2>
+_Tp __brick_transform_reduce(_ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _Tp, _BinaryOperation1,
+                             _BinaryOperation2,
+                             /*__is_vector=*/std::false_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Tp,
+          class _BinaryOperation1, class _BinaryOperation2>
+_Tp
+__pattern_transform_reduce(_Tag, _ExecutionPolicy&&, _ForwardIterator1, _ForwardIterator1, _ForwardIterator2, _Tp,
+                           _BinaryOperation1, _BinaryOperation2) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _Tp, class _BinaryOperation1, class _BinaryOperation2>
+_Tp
+__pattern_transform_reduce(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator1,
+                           _RandomAccessIterator1, _RandomAccessIterator2, _Tp, _BinaryOperation1, _BinaryOperation2);
+
+//------------------------------------------------------------------------
+// transform_reduce (version with unary and binary functions)
+//------------------------------------------------------------------------
+
+template <class _RandomAccessIterator, class _Tp, class _UnaryOperation, class _BinaryOperation>
+_Tp __brick_transform_reduce(_RandomAccessIterator, _RandomAccessIterator, _Tp, _BinaryOperation, _UnaryOperation,
+                             /*is_vector=*/std::true_type) noexcept;
+
+template <class _ForwardIterator, class _Tp, class _BinaryOperation, class _UnaryOperation>
+_Tp __brick_transform_reduce(_ForwardIterator, _ForwardIterator, _Tp, _BinaryOperation, _UnaryOperation,
+                             /*is_vector=*/std::false_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _Tp, class _BinaryOperation,
+          class _UnaryOperation>
+_Tp
+__pattern_transform_reduce(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, _Tp, _BinaryOperation,
+                           _UnaryOperation) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Tp, class _BinaryOperation,
+          class _UnaryOperation>
+_Tp
+__pattern_transform_reduce(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                           _Tp, _BinaryOperation, _UnaryOperation);
+
+//------------------------------------------------------------------------
+// transform_exclusive_scan
+//
+// walk3 evaluates f(x,y,z) for (x,y,z) drawn from [first1,last1), [first2,...), [first3,...)
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _OutputIterator, class _UnaryOperation, class _Tp, class _BinaryOperation>
+std::pair<_OutputIterator, _Tp> __brick_transform_scan(_ForwardIterator, _ForwardIterator, _OutputIterator,
+                                                       _UnaryOperation, _Tp, _BinaryOperation,
+                                                       /*Inclusive*/ std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _OutputIterator, class _UnaryOperation, class _Tp, class _BinaryOperation>
+std::pair<_OutputIterator, _Tp> __brick_transform_scan(_RandomAccessIterator, _RandomAccessIterator, _OutputIterator,
+                                                       _UnaryOperation, _Tp, _BinaryOperation,
+                                                       /*Inclusive*/ std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _OutputIterator, class _UnaryOperation,
+          class _Tp, class _BinaryOperation, class _Inclusive>
+_OutputIterator
+__pattern_transform_scan(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, _OutputIterator, _UnaryOperation,
+                         _Tp, _BinaryOperation, _Inclusive) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _OutputIterator,
+          class _UnaryOperation, class _Tp, class _BinaryOperation, class _Inclusive>
+typename std::enable_if<!std::is_floating_point<_Tp>::value, _OutputIterator>::type
+__pattern_transform_scan(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&&, _RandomAccessIterator,
+                         _RandomAccessIterator, _OutputIterator, _UnaryOperation, _Tp, _BinaryOperation, _Inclusive);
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _OutputIterator,
+          class _UnaryOperation, class _Tp, class _BinaryOperation, class _Inclusive>
+typename std::enable_if<std::is_floating_point<_Tp>::value, _OutputIterator>::type
+__pattern_transform_scan(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator, _RandomAccessIterator,
+                         _OutputIterator, _UnaryOperation, _Tp, _BinaryOperation, _Inclusive);
+
+//------------------------------------------------------------------------
+// adjacent_difference
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _OutputIterator, class _BinaryOperation>
+_OutputIterator __brick_adjacent_difference(_ForwardIterator, _ForwardIterator, _OutputIterator, _BinaryOperation,
+                                            /*is_vector*/ std::false_type) noexcept;
+
+template <class _RandomAccessIterator, class _OutputIterator, class _BinaryOperation>
+_OutputIterator __brick_adjacent_difference(_RandomAccessIterator, _RandomAccessIterator, _OutputIterator,
+                                            _BinaryOperation,
+                                            /*is_vector*/ std::true_type) noexcept;
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _OutputIterator, class _BinaryOperation>
+_OutputIterator
+__pattern_adjacent_difference(_Tag, _ExecutionPolicy&&, _ForwardIterator, _ForwardIterator, _OutputIterator,
+                              _BinaryOperation) noexcept;
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _OutputIterator,
+          class _BinaryOperation>
+_OutputIterator
+__pattern_adjacent_difference(__parallel_tag<_IsVector>, _ExecutionPolicy&&, _RandomAccessIterator,
+                              _RandomAccessIterator, _OutputIterator, _BinaryOperation);
+
+} // namespace __internal
+} // namespace __pstl
+
+_PSTL_HIDE_FROM_ABI_POP
+
+#endif /* _PSTL_NUMERIC_FWD_H */
diff --git a/pstl/include/pstl/internal/numeric_impl.h b/pstl/include/pstl/internal/numeric_impl.h
new file mode 100644
index 0000000..a0387ae
--- /dev/null
+++ b/pstl/include/pstl/internal/numeric_impl.h
@@ -0,0 +1,383 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_NUMERIC_IMPL_H
+#define _PSTL_NUMERIC_IMPL_H
+
+#include <iterator>
+#include <type_traits>
+#include <numeric>
+
+#include "parallel_backend.h"
+#include "pstl_config.h"
+#include "execution_impl.h"
+#include "unseq_backend_simd.h"
+#include "algorithm_fwd.h"
+
+_PSTL_HIDE_FROM_ABI_PUSH
+
+namespace __pstl
+{
+namespace __internal
+{
+
+//------------------------------------------------------------------------
+// transform_reduce (version with two binary functions, according to draft N4659)
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _Tp, class _BinaryOperation1, class _BinaryOperation2>
+_Tp
+__brick_transform_reduce(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _Tp __init,
+                         _BinaryOperation1 __binary_op1, _BinaryOperation2 __binary_op2,
+                         /*is_vector=*/std::false_type) noexcept
+{
+    return std::inner_product(__first1, __last1, __first2, __init, __binary_op1, __binary_op2);
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _Tp, class _BinaryOperation1,
+          class _BinaryOperation2>
+_Tp
+__brick_transform_reduce(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
+                         _RandomAccessIterator2 __first2, _Tp __init, _BinaryOperation1 __binary_op1,
+                         _BinaryOperation2 __binary_op2,
+                         /*is_vector=*/std::true_type) noexcept
+{
+    typedef typename std::iterator_traits<_RandomAccessIterator1>::difference_type _DifferenceType;
+    return __unseq_backend::__simd_transform_reduce(
+        __last1 - __first1, __init, __binary_op1,
+        [=, &__binary_op2](_DifferenceType __i) { return __binary_op2(__first1[__i], __first2[__i]); });
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator1, class _ForwardIterator2, class _Tp,
+          class _BinaryOperation1, class _BinaryOperation2>
+_Tp
+__pattern_transform_reduce(_Tag, _ExecutionPolicy&&, _ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                           _ForwardIterator2 __first2, _Tp __init, _BinaryOperation1 __binary_op1,
+                           _BinaryOperation2 __binary_op2) noexcept
+{
+    return __brick_transform_reduce(__first1, __last1, __first2, __init, __binary_op1, __binary_op2,
+                                    typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _Tp, class _BinaryOperation1, class _BinaryOperation2>
+_Tp
+__pattern_transform_reduce(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator1 __first1,
+                           _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2, _Tp __init,
+                           _BinaryOperation1 __binary_op1, _BinaryOperation2 __binary_op2)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    return __internal::__except_handler(
+        [&]()
+        {
+            return __par_backend::__parallel_transform_reduce(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first1, __last1,
+                [__first1, __first2, __binary_op2](_RandomAccessIterator1 __i) mutable
+                { return __binary_op2(*__i, *(__first2 + (__i - __first1))); },
+                __init,
+                __binary_op1, // Combine
+                [__first1, __first2, __binary_op1, __binary_op2](_RandomAccessIterator1 __i, _RandomAccessIterator1 __j,
+                                                                 _Tp __init) -> _Tp
+                {
+                    return __internal::__brick_transform_reduce(__i, __j, __first2 + (__i - __first1), __init,
+                                                                __binary_op1, __binary_op2, _IsVector{});
+                });
+        });
+}
+
+//------------------------------------------------------------------------
+// transform_reduce (version with unary and binary functions)
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _Tp, class _BinaryOperation, class _UnaryOperation>
+_Tp
+__brick_transform_reduce(_ForwardIterator __first, _ForwardIterator __last, _Tp __init, _BinaryOperation __binary_op,
+                         _UnaryOperation __unary_op, /*is_vector=*/std::false_type) noexcept
+{
+    return std::transform_reduce(__first, __last, __init, __binary_op, __unary_op);
+}
+
+template <class _RandomAccessIterator, class _Tp, class _UnaryOperation, class _BinaryOperation>
+_Tp
+__brick_transform_reduce(_RandomAccessIterator __first, _RandomAccessIterator __last, _Tp __init,
+                         _BinaryOperation __binary_op, _UnaryOperation __unary_op,
+                         /*is_vector=*/std::true_type) noexcept
+{
+    typedef typename std::iterator_traits<_RandomAccessIterator>::difference_type _DifferenceType;
+    return __unseq_backend::__simd_transform_reduce(
+        __last - __first, __init, __binary_op,
+        [=, &__unary_op](_DifferenceType __i) { return __unary_op(__first[__i]); });
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _Tp, class _BinaryOperation,
+          class _UnaryOperation>
+_Tp
+__pattern_transform_reduce(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last, _Tp __init,
+                           _BinaryOperation __binary_op, _UnaryOperation __unary_op) noexcept
+{
+    return __internal::__brick_transform_reduce(__first, __last, __init, __binary_op, __unary_op,
+                                                typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _Tp, class _BinaryOperation,
+          class _UnaryOperation>
+_Tp
+__pattern_transform_reduce(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                           _RandomAccessIterator __last, _Tp __init, _BinaryOperation __binary_op,
+                           _UnaryOperation __unary_op)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    return __internal::__except_handler(
+        [&]()
+        {
+            return __par_backend::__parallel_transform_reduce(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                [__unary_op](_RandomAccessIterator __i) mutable { return __unary_op(*__i); }, __init, __binary_op,
+                [__unary_op, __binary_op](_RandomAccessIterator __i, _RandomAccessIterator __j, _Tp __init) {
+                    return __internal::__brick_transform_reduce(__i, __j, __init, __binary_op, __unary_op, _IsVector{});
+                });
+        });
+}
+
+//------------------------------------------------------------------------
+// transform_exclusive_scan
+//
+// walk3 evaluates f(x,y,z) for (x,y,z) drawn from [first1,last1), [first2,...), [first3,...)
+//------------------------------------------------------------------------
+
+// Exclusive form
+template <class _ForwardIterator, class _OutputIterator, class _UnaryOperation, class _Tp, class _BinaryOperation>
+std::pair<_OutputIterator, _Tp>
+__brick_transform_scan(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator __result,
+                       _UnaryOperation __unary_op, _Tp __init, _BinaryOperation __binary_op,
+                       /*Inclusive*/ std::false_type, /*is_vector=*/std::false_type) noexcept
+{
+    for (; __first != __last; ++__first, ++__result)
+    {
+        *__result = __init;
+        _PSTL_PRAGMA_FORCEINLINE
+        __init = __binary_op(__init, __unary_op(*__first));
+    }
+    return std::make_pair(__result, __init);
+}
+
+// Inclusive form
+template <class _RandomAccessIterator, class _OutputIterator, class _UnaryOperation, class _Tp, class _BinaryOperation>
+std::pair<_OutputIterator, _Tp>
+__brick_transform_scan(_RandomAccessIterator __first, _RandomAccessIterator __last, _OutputIterator __result,
+                       _UnaryOperation __unary_op, _Tp __init, _BinaryOperation __binary_op,
+                       /*Inclusive*/ std::true_type, /*is_vector=*/std::false_type) noexcept
+{
+    for (; __first != __last; ++__first, ++__result)
+    {
+        _PSTL_PRAGMA_FORCEINLINE
+        __init = __binary_op(__init, __unary_op(*__first));
+        *__result = __init;
+    }
+    return std::make_pair(__result, __init);
+}
+
+// type is arithmetic and binary operation is a user defined operation.
+template <typename _Tp, typename _BinaryOperation>
+using is_arithmetic_udop = std::integral_constant<bool, std::is_arithmetic<_Tp>::value &&
+                                                            !std::is_same<_BinaryOperation, std::plus<_Tp>>::value>;
+
+// [restriction] - T shall be DefaultConstructible.
+// [violation] - default ctor of T shall set the identity value for binary_op.
+template <class _RandomAccessIterator, class _OutputIterator, class _UnaryOperation, class _Tp, class _BinaryOperation,
+          class _Inclusive>
+typename std::enable_if<!is_arithmetic_udop<_Tp, _BinaryOperation>::value, std::pair<_OutputIterator, _Tp>>::type
+__brick_transform_scan(_RandomAccessIterator __first, _RandomAccessIterator __last, _OutputIterator __result,
+                       _UnaryOperation __unary_op, _Tp __init, _BinaryOperation __binary_op, _Inclusive,
+                       /*is_vector=*/std::true_type) noexcept
+{
+#if defined(_PSTL_UDS_PRESENT)
+    return __unseq_backend::__simd_scan(__first, __last - __first, __result, __unary_op, __init, __binary_op,
+                                        _Inclusive());
+#else
+    // We need to call serial brick here to call function for inclusive and exclusive scan that depends on _Inclusive() value
+    return __internal::__brick_transform_scan(__first, __last, __result, __unary_op, __init, __binary_op, _Inclusive(),
+                                              /*is_vector=*/std::false_type());
+#endif
+}
+
+template <class _RandomAccessIterator, class _OutputIterator, class _UnaryOperation, class _Tp, class _BinaryOperation,
+          class _Inclusive>
+typename std::enable_if<is_arithmetic_udop<_Tp, _BinaryOperation>::value, std::pair<_OutputIterator, _Tp>>::type
+__brick_transform_scan(_RandomAccessIterator __first, _RandomAccessIterator __last, _OutputIterator __result,
+                       _UnaryOperation __unary_op, _Tp __init, _BinaryOperation __binary_op, _Inclusive,
+                       /*is_vector=*/std::true_type) noexcept
+{
+    return __internal::__brick_transform_scan(__first, __last, __result, __unary_op, __init, __binary_op, _Inclusive(),
+                                              /*is_vector=*/std::false_type());
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _OutputIterator, class _UnaryOperation,
+          class _Tp, class _BinaryOperation, class _Inclusive>
+_OutputIterator
+__pattern_transform_scan(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last,
+                         _OutputIterator __result, _UnaryOperation __unary_op, _Tp __init, _BinaryOperation __binary_op,
+                         _Inclusive) noexcept
+{
+    return __internal::__brick_transform_scan(__first, __last, __result, __unary_op, __init, __binary_op, _Inclusive(),
+                                              typename _Tag::__is_vector{})
+        .first;
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _OutputIterator,
+          class _UnaryOperation, class _Tp, class _BinaryOperation, class _Inclusive>
+typename std::enable_if<!std::is_floating_point<_Tp>::value, _OutputIterator>::type
+__pattern_transform_scan(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                         _RandomAccessIterator __last, _OutputIterator __result, _UnaryOperation __unary_op, _Tp __init,
+                         _BinaryOperation __binary_op, _Inclusive)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    typedef typename std::iterator_traits<_RandomAccessIterator>::difference_type _DifferenceType;
+
+    return __internal::__except_handler(
+        [&]()
+        {
+            __par_backend::__parallel_transform_scan(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __last - __first,
+                [__first, __unary_op](_DifferenceType __i) mutable { return __unary_op(__first[__i]); }, __init,
+                __binary_op,
+                [__first, __unary_op, __binary_op](_DifferenceType __i, _DifferenceType __j, _Tp __init)
+                {
+                    // Execute serial __brick_transform_reduce, due to the explicit SIMD vectorization (reduction) requires a commutative operation for the guarantee of correct scan.
+                    return __internal::__brick_transform_reduce(__first + __i, __first + __j, __init, __binary_op,
+                                                                __unary_op,
+                                                                /*__is_vector*/ std::false_type());
+                },
+                [__first, __unary_op, __binary_op, __result](_DifferenceType __i, _DifferenceType __j, _Tp __init)
+                {
+                    return __internal::__brick_transform_scan(__first + __i, __first + __j, __result + __i, __unary_op,
+                                                              __init, __binary_op, _Inclusive(), _IsVector{})
+                        .second;
+                });
+            return __result + (__last - __first);
+        });
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator, class _OutputIterator,
+          class _UnaryOperation, class _Tp, class _BinaryOperation, class _Inclusive>
+typename std::enable_if<std::is_floating_point<_Tp>::value, _OutputIterator>::type
+__pattern_transform_scan(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec, _RandomAccessIterator __first,
+                         _RandomAccessIterator __last, _OutputIterator __result, _UnaryOperation __unary_op, _Tp __init,
+                         _BinaryOperation __binary_op, _Inclusive)
+{
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    typedef typename std::iterator_traits<_RandomAccessIterator>::difference_type _DifferenceType;
+    _DifferenceType __n = __last - __first;
+
+    if (__n <= 0)
+    {
+        return __result;
+    }
+    return __internal::__except_handler(
+        [&]()
+        {
+            __par_backend::__parallel_strict_scan(
+                __backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __n, __init,
+                [__first, __unary_op, __binary_op, __result](_DifferenceType __i, _DifferenceType __len)
+                {
+                    return __internal::__brick_transform_scan(__first + __i, __first + (__i + __len), __result + __i,
+                                                              __unary_op, _Tp{}, __binary_op, _Inclusive(), _IsVector{})
+                        .second;
+                },
+                __binary_op,
+                [__result, &__binary_op](_DifferenceType __i, _DifferenceType __len, _Tp __initial)
+                {
+                    return *(std::transform(__result + __i, __result + __i + __len, __result + __i,
+                                            [&__initial, &__binary_op](const _Tp& __x)
+                                            {
+                                                _PSTL_PRAGMA_FORCEINLINE
+                                                return __binary_op(__initial, __x);
+                                            }) -
+                             1);
+                },
+                [](_Tp) {});
+            return __result + (__last - __first);
+        });
+}
+
+//------------------------------------------------------------------------
+// adjacent_difference
+//------------------------------------------------------------------------
+
+template <class _ForwardIterator, class _OutputIterator, class _BinaryOperation>
+_OutputIterator
+__brick_adjacent_difference(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator __d_first,
+                            _BinaryOperation __op, /*is_vector*/ std::false_type) noexcept
+{
+    return std::adjacent_difference(__first, __last, __d_first, __op);
+}
+
+template <class _RandomAccessIterator1, class _RandomAccessIterator2, class BinaryOperation>
+_RandomAccessIterator2
+__brick_adjacent_difference(_RandomAccessIterator1 __first, _RandomAccessIterator1 __last,
+                            _RandomAccessIterator2 __d_first, BinaryOperation __op,
+                            /*is_vector=*/std::true_type) noexcept
+{
+    _PSTL_ASSERT(__first != __last);
+
+    typedef typename std::iterator_traits<_RandomAccessIterator1>::reference _ReferenceType1;
+    typedef typename std::iterator_traits<_RandomAccessIterator2>::reference _ReferenceType2;
+
+    auto __n = __last - __first;
+    *__d_first = *__first;
+    return __unseq_backend::__simd_walk_3(
+        __first + 1, __n - 1, __first, __d_first + 1,
+        [&__op](_ReferenceType1 __x, _ReferenceType1 __y, _ReferenceType2 __z) { __z = __op(__x, __y); });
+}
+
+template <class _Tag, class _ExecutionPolicy, class _ForwardIterator, class _OutputIterator, class _BinaryOperation>
+_OutputIterator
+__pattern_adjacent_difference(_Tag, _ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last,
+                              _OutputIterator __d_first, _BinaryOperation __op) noexcept
+{
+    return __internal::__brick_adjacent_difference(__first, __last, __d_first, __op, typename _Tag::__is_vector{});
+}
+
+template <class _IsVector, class _ExecutionPolicy, class _RandomAccessIterator1, class _RandomAccessIterator2,
+          class _BinaryOperation>
+_RandomAccessIterator2
+__pattern_adjacent_difference(__parallel_tag<_IsVector> __tag, _ExecutionPolicy&& __exec,
+                              _RandomAccessIterator1 __first, _RandomAccessIterator1 __last,
+                              _RandomAccessIterator2 __d_first, _BinaryOperation __op)
+{
+    _PSTL_ASSERT(__first != __last);
+    typedef typename std::iterator_traits<_RandomAccessIterator1>::reference _ReferenceType1;
+    typedef typename std::iterator_traits<_RandomAccessIterator2>::reference _ReferenceType2;
+
+    using __backend_tag = typename decltype(__tag)::__backend_tag;
+
+    *__d_first = *__first;
+    __par_backend::__parallel_for(__backend_tag{}, std::forward<_ExecutionPolicy>(__exec), __first, __last - 1,
+                                  [&__op, __d_first, __first](_RandomAccessIterator1 __b, _RandomAccessIterator1 __e)
+                                  {
+                                      _RandomAccessIterator2 __d_b = __d_first + (__b - __first);
+                                      __internal::__brick_walk3(
+                                          __b, __e, __b + 1, __d_b + 1,
+                                          [&__op](_ReferenceType1 __x, _ReferenceType1 __y, _ReferenceType2 __z)
+                                          { __z = __op(__y, __x); },
+                                          _IsVector{});
+                                  });
+    return __d_first + (__last - __first);
+}
+
+} // namespace __internal
+} // namespace __pstl
+
+_PSTL_HIDE_FROM_ABI_POP
+
+#endif /* _PSTL_NUMERIC_IMPL_H */
diff --git a/pstl/include/pstl/internal/omp/parallel_for.h b/pstl/include/pstl/internal/omp/parallel_for.h
new file mode 100644
index 0000000..0f841e5
--- /dev/null
+++ b/pstl/include/pstl/internal/omp/parallel_for.h
@@ -0,0 +1,64 @@
+// -*- C++ -*-
+// -*-===----------------------------------------------------------------------===//
+//
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_INTERNAL_OMP_PARALLEL_FOR_H
+#define _PSTL_INTERNAL_OMP_PARALLEL_FOR_H
+
+#include <cstddef>
+
+#include "util.h"
+
+namespace __pstl
+{
+namespace __omp_backend
+{
+
+template <class _Index, class _Fp>
+void
+__parallel_for_body(_Index __first, _Index __last, _Fp __f)
+{
+    // initial partition of the iteration space into chunks
+    auto __policy = __omp_backend::__chunk_partitioner(__first, __last);
+
+    // To avoid over-subscription we use taskloop for the nested parallelism
+    _PSTL_PRAGMA(omp taskloop untied mergeable)
+    for (std::size_t __chunk = 0; __chunk < __policy.__n_chunks; ++__chunk)
+    {
+        __pstl::__omp_backend::__process_chunk(__policy, __first, __chunk, __f);
+    }
+}
+
+//------------------------------------------------------------------------
+// Notation:
+// Evaluation of brick f[i,j) for each subrange [i,j) of [first, last)
+//------------------------------------------------------------------------
+
+template <class _ExecutionPolicy, class _Index, class _Fp>
+void
+__parallel_for(__pstl::__internal::__openmp_backend_tag, _ExecutionPolicy&&, _Index __first, _Index __last, _Fp __f)
+{
+    if (omp_in_parallel())
+    {
+        // we don't create a nested parallel region in an existing parallel
+        // region: just create tasks
+        __pstl::__omp_backend::__parallel_for_body(__first, __last, __f);
+    }
+    else
+    {
+        // in any case (nested or non-nested) one parallel region is created and
+        // only one thread creates a set of tasks
+        _PSTL_PRAGMA(omp parallel)
+        _PSTL_PRAGMA(omp single nowait) { __pstl::__omp_backend::__parallel_for_body(__first, __last, __f); }
+    }
+}
+
+} // namespace __omp_backend
+} // namespace __pstl
+#endif // _PSTL_INTERNAL_OMP_PARALLEL_FOR_H
diff --git a/pstl/include/pstl/internal/omp/parallel_for_each.h b/pstl/include/pstl/internal/omp/parallel_for_each.h
new file mode 100644
index 0000000..b9bfb05
--- /dev/null
+++ b/pstl/include/pstl/internal/omp/parallel_for_each.h
@@ -0,0 +1,59 @@
+// -*- C++ -*-
+// -*-===----------------------------------------------------------------------===//
+//
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_INTERNAL_OMP_PARALLEL_FOR_EACH_H
+#define _PSTL_INTERNAL_OMP_PARALLEL_FOR_EACH_H
+
+#include "util.h"
+
+namespace __pstl
+{
+namespace __omp_backend
+{
+
+template <class _ForwardIterator, class _Fp>
+void
+__parallel_for_each_body(_ForwardIterator __first, _ForwardIterator __last, _Fp __f)
+{
+    using DifferenceType = typename std::iterator_traits<_ForwardIterator>::difference_type;
+    // TODO: Think of an approach to remove the std::distance call
+    auto __size = std::distance(__first, __last);
+
+    _PSTL_PRAGMA(omp taskloop untied mergeable)
+    for (DifferenceType __index = 0; __index < __size; ++__index)
+    {
+        // TODO: Think of an approach to remove the increment here each time.
+        auto __iter = std::next(__first, __index);
+        __f(*__iter);
+    }
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Fp>
+void
+__parallel_for_each(_ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last, _Fp __f)
+{
+    if (omp_in_parallel())
+    {
+        // we don't create a nested parallel region in an existing parallel
+        // region: just create tasks
+        __pstl::__omp_backend::__parallel_for_each_body(__first, __last, __f);
+    }
+    else
+    {
+        // in any case (nested or non-nested) one parallel region is created and
+        // only one thread creates a set of tasks
+        _PSTL_PRAGMA(omp parallel)
+        _PSTL_PRAGMA(omp single nowait) { __pstl::__omp_backend::__parallel_for_each_body(__first, __last, __f); }
+    }
+}
+
+} // namespace __omp_backend
+} // namespace __pstl
+#endif // _PSTL_INTERNAL_OMP_PARALLEL_FOR_EACH_H
diff --git a/pstl/include/pstl/internal/omp/parallel_invoke.h b/pstl/include/pstl/internal/omp/parallel_invoke.h
new file mode 100644
index 0000000..045ccbe
--- /dev/null
+++ b/pstl/include/pstl/internal/omp/parallel_invoke.h
@@ -0,0 +1,50 @@
+// -*- C++ -*-
+// -*-===----------------------------------------------------------------------===//
+//
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_INTERNAL_OMP_PARALLEL_INVOKE_H
+#define _PSTL_INTERNAL_OMP_PARALLEL_INVOKE_H
+
+#include "util.h"
+
+namespace __pstl
+{
+namespace __omp_backend
+{
+
+template <typename _F1, typename _F2>
+void
+__parallel_invoke_body(_F1&& __f1, _F2&& __f2)
+{
+    _PSTL_PRAGMA(omp taskgroup)
+    {
+        _PSTL_PRAGMA(omp task untied mergeable) { std::forward<_F1>(__f1)(); }
+        _PSTL_PRAGMA(omp task untied mergeable) { std::forward<_F2>(__f2)(); }
+    }
+}
+
+template <class _ExecutionPolicy, typename _F1, typename _F2>
+void
+__parallel_invoke(__pstl::__internal::__openmp_backend_tag, _ExecutionPolicy&&, _F1&& __f1, _F2&& __f2)
+{
+    if (omp_in_parallel())
+    {
+        __pstl::__omp_backend::__parallel_invoke_body(std::forward<_F1>(__f1), std::forward<_F2>(__f2));
+    }
+    else
+    {
+        _PSTL_PRAGMA(omp parallel)
+        _PSTL_PRAGMA(omp single nowait)
+        __pstl::__omp_backend::__parallel_invoke_body(std::forward<_F1>(__f1), std::forward<_F2>(__f2));
+    }
+}
+
+} // namespace __omp_backend
+} // namespace __pstl
+#endif // _PSTL_INTERNAL_OMP_PARALLEL_INVOKE_H
diff --git a/pstl/include/pstl/internal/omp/parallel_merge.h b/pstl/include/pstl/internal/omp/parallel_merge.h
new file mode 100644
index 0000000..e6f82c5
--- /dev/null
+++ b/pstl/include/pstl/internal/omp/parallel_merge.h
@@ -0,0 +1,98 @@
+// -*- C++ -*-
+// -*-===----------------------------------------------------------------------===//
+//
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_INTERNAL_OMP_PARALLEL_MERGE_H
+#define _PSTL_INTERNAL_OMP_PARALLEL_MERGE_H
+
+#include "util.h"
+
+namespace __pstl
+{
+namespace __omp_backend
+{
+
+template <typename _RandomAccessIterator1, typename _RandomAccessIterator2, typename _RandomAccessIterator3,
+          typename _Compare, typename _LeafMerge>
+void
+__parallel_merge_body(std::size_t __size_x, std::size_t __size_y, _RandomAccessIterator1 __xs,
+                      _RandomAccessIterator1 __xe, _RandomAccessIterator2 __ys, _RandomAccessIterator2 __ye,
+                      _RandomAccessIterator3 __zs, _Compare __comp, _LeafMerge __leaf_merge)
+{
+
+    if (__size_x + __size_y <= __omp_backend::__default_chunk_size)
+    {
+        __leaf_merge(__xs, __xe, __ys, __ye, __zs, __comp);
+        return;
+    }
+
+    _RandomAccessIterator1 __xm;
+    _RandomAccessIterator2 __ym;
+
+    if (__size_x < __size_y)
+    {
+        __ym = __ys + (__size_y / 2);
+        __xm = std::upper_bound(__xs, __xe, *__ym, __comp);
+    }
+    else
+    {
+        __xm = __xs + (__size_x / 2);
+        __ym = std::lower_bound(__ys, __ye, *__xm, __comp);
+    }
+
+    auto __zm = __zs + (__xm - __xs) + (__ym - __ys);
+
+    _PSTL_PRAGMA(omp task untied mergeable default(none)
+                     firstprivate(__xs, __xm, __ys, __ym, __zs, __comp, __leaf_merge))
+    __pstl::__omp_backend::__parallel_merge_body(__xm - __xs, __ym - __ys, __xs, __xm, __ys, __ym, __zs, __comp,
+                                                      __leaf_merge);
+
+    _PSTL_PRAGMA(omp task untied mergeable default(none)
+                     firstprivate(__xm, __xe, __ym, __ye, __zm, __comp, __leaf_merge))
+    __pstl::__omp_backend::__parallel_merge_body(__xe - __xm, __ye - __ym, __xm, __xe, __ym, __ye, __zm, __comp,
+                                                      __leaf_merge);
+
+    _PSTL_PRAGMA(omp taskwait)
+}
+
+template <class _ExecutionPolicy, typename _RandomAccessIterator1, typename _RandomAccessIterator2,
+          typename _RandomAccessIterator3, typename _Compare, typename _LeafMerge>
+void
+__parallel_merge(__pstl::__internal::__openmp_backend_tag, _ExecutionPolicy&& /*__exec*/, _RandomAccessIterator1 __xs,
+                 _RandomAccessIterator1 __xe, _RandomAccessIterator2 __ys, _RandomAccessIterator2 __ye,
+                 _RandomAccessIterator3 __zs, _Compare __comp, _LeafMerge __leaf_merge)
+
+{
+    std::size_t __size_x = __xe - __xs;
+    std::size_t __size_y = __ye - __ys;
+
+    /*
+     * Run the merge in parallel by chunking it up. Use the smaller range (if any) as the iteration range, and the
+     * larger range as the search range.
+     */
+
+    if (omp_in_parallel())
+    {
+        __pstl::__omp_backend::__parallel_merge_body(__size_x, __size_y, __xs, __xe, __ys, __ye, __zs, __comp,
+                                                          __leaf_merge);
+    }
+    else
+    {
+        _PSTL_PRAGMA(omp parallel)
+        {
+            _PSTL_PRAGMA(omp single nowait)
+            __pstl::__omp_backend::__parallel_merge_body(__size_x, __size_y, __xs, __xe, __ys, __ye, __zs, __comp,
+                                                              __leaf_merge);
+        }
+    }
+}
+
+} // namespace __omp_backend
+} // namespace __pstl
+#endif // _PSTL_INTERNAL_OMP_PARALLEL_MERGE_H
diff --git a/pstl/include/pstl/internal/omp/parallel_reduce.h b/pstl/include/pstl/internal/omp/parallel_reduce.h
new file mode 100644
index 0000000..841d48f
--- /dev/null
+++ b/pstl/include/pstl/internal/omp/parallel_reduce.h
@@ -0,0 +1,73 @@
+// -*- C++ -*-
+// -*-===----------------------------------------------------------------------===//
+//
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_INTERNAL_OMP_PARALLEL_REDUCE_H
+#define _PSTL_INTERNAL_OMP_PARALLEL_REDUCE_H
+
+#include "util.h"
+
+namespace __pstl
+{
+namespace __omp_backend
+{
+
+template <class _RandomAccessIterator, class _Value, typename _RealBody, typename _Reduction>
+_Value
+__parallel_reduce_body(_RandomAccessIterator __first, _RandomAccessIterator __last, _Value __identity,
+                       _RealBody __real_body, _Reduction __reduce)
+{
+    if (__should_run_serial(__first, __last))
+    {
+        return __real_body(__first, __last, __identity);
+    }
+
+    auto __middle = __first + ((__last - __first) / 2);
+    _Value __v1(__identity), __v2(__identity);
+    __parallel_invoke_body(
+        [&]() { __v1 = __parallel_reduce_body(__first, __middle, __identity, __real_body, __reduce); },
+        [&]() { __v2 = __parallel_reduce_body(__middle, __last, __identity, __real_body, __reduce); });
+
+    return __reduce(__v1, __v2);
+}
+
+//------------------------------------------------------------------------
+// Notation:
+//      r(i,j,init) returns reduction of init with reduction over [i,j)
+//      c(x,y) combines values x and y that were the result of r
+//------------------------------------------------------------------------
+
+template <class _ExecutionPolicy, class _RandomAccessIterator, class _Value, typename _RealBody, typename _Reduction>
+_Value
+__parallel_reduce(__pstl::__internal::__openmp_backend_tag, _ExecutionPolicy&&, _RandomAccessIterator __first,
+                  _RandomAccessIterator __last, _Value __identity, _RealBody __real_body, _Reduction __reduction)
+{
+    // We don't create a nested parallel region in an existing parallel region:
+    // just create tasks.
+    if (omp_in_parallel())
+    {
+        return __pstl::__omp_backend::__parallel_reduce_body(__first, __last, __identity, __real_body, __reduction);
+    }
+
+    // In any case (nested or non-nested) one parallel region is created and only
+    // one thread creates a set of tasks.
+    _Value __res = __identity;
+
+    _PSTL_PRAGMA(omp parallel)
+    _PSTL_PRAGMA(omp single nowait)
+    {
+        __res = __pstl::__omp_backend::__parallel_reduce_body(__first, __last, __identity, __real_body, __reduction);
+    }
+
+    return __res;
+}
+
+} // namespace __omp_backend
+} // namespace __pstl
+#endif // _PSTL_INTERNAL_OMP_PARALLEL_REDUCE_H
diff --git a/pstl/include/pstl/internal/omp/parallel_scan.h b/pstl/include/pstl/internal/omp/parallel_scan.h
new file mode 100644
index 0000000..f3eb967
--- /dev/null
+++ b/pstl/include/pstl/internal/omp/parallel_scan.h
@@ -0,0 +1,136 @@
+// -*- C++ -*-
+// -*-===----------------------------------------------------------------------===//
+//
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_INTERNAL_OMP_PARALLEL_SCAN_H
+#define _PSTL_INTERNAL_OMP_PARALLEL_SCAN_H
+
+#include "parallel_invoke.h"
+
+namespace __pstl
+{
+namespace __omp_backend
+{
+
+template <typename _Index>
+_Index
+__split(_Index __m)
+{
+    _Index __k = 1;
+    while (2 * __k < __m)
+        __k *= 2;
+    return __k;
+}
+
+template <typename _Index, typename _Tp, typename _Rp, typename _Cp>
+void
+__upsweep(_Index __i, _Index __m, _Index __tilesize, _Tp* __r, _Index __lastsize, _Rp __reduce, _Cp __combine)
+{
+    if (__m == 1)
+        __r[0] = __reduce(__i * __tilesize, __lastsize);
+    else
+    {
+        _Index __k = __split(__m);
+        __omp_backend::__parallel_invoke_body(
+            [=] { __omp_backend::__upsweep(__i, __k, __tilesize, __r, __tilesize, __reduce, __combine); },
+            [=] {
+                __omp_backend::__upsweep(__i + __k, __m - __k, __tilesize, __r + __k, __lastsize, __reduce, __combine);
+            });
+        if (__m == 2 * __k)
+            __r[__m - 1] = __combine(__r[__k - 1], __r[__m - 1]);
+    }
+}
+
+template <typename _Index, typename _Tp, typename _Cp, typename _Sp>
+void
+__downsweep(_Index __i, _Index __m, _Index __tilesize, _Tp* __r, _Index __lastsize, _Tp __initial, _Cp __combine,
+            _Sp __scan)
+{
+    if (__m == 1)
+        __scan(__i * __tilesize, __lastsize, __initial);
+    else
+    {
+        const _Index __k = __split(__m);
+        __omp_backend::__parallel_invoke_body(
+            [=] { __omp_backend::__downsweep(__i, __k, __tilesize, __r, __tilesize, __initial, __combine, __scan); },
+            // Assumes that __combine never throws.
+            // TODO: Consider adding a requirement for user functors to be constant.
+            [=, &__combine]
+            {
+                __omp_backend::__downsweep(__i + __k, __m - __k, __tilesize, __r + __k, __lastsize,
+                                           __combine(__initial, __r[__k - 1]), __combine, __scan);
+            });
+    }
+}
+
+template <typename _ExecutionPolicy, typename _Index, typename _Tp, typename _Rp, typename _Cp, typename _Sp,
+          typename _Ap>
+void
+__parallel_strict_scan_body(_Index __n, _Tp __initial, _Rp __reduce, _Cp __combine, _Sp __scan, _Ap __apex)
+{
+    _Index __p = omp_get_num_threads();
+    const _Index __slack = 4;
+    _Index __tilesize = (__n - 1) / (__slack * __p) + 1;
+    _Index __m = (__n - 1) / __tilesize;
+    __buffer<_Tp> __buf(__m + 1);
+    _Tp* __r = __buf.get();
+
+    __omp_backend::__upsweep(_Index(0), _Index(__m + 1), __tilesize, __r, __n - __m * __tilesize, __reduce, __combine);
+
+    std::size_t __k = __m + 1;
+    _Tp __t = __r[__k - 1];
+    while ((__k &= __k - 1))
+    {
+        __t = __combine(__r[__k - 1], __t);
+    }
+
+    __apex(__combine(__initial, __t));
+    __omp_backend::__downsweep(_Index(0), _Index(__m + 1), __tilesize, __r, __n - __m * __tilesize, __initial,
+                               __combine, __scan);
+}
+
+template <class _ExecutionPolicy, typename _Index, typename _Tp, typename _Rp, typename _Cp, typename _Sp, typename _Ap>
+void
+__parallel_strict_scan(__pstl::__internal::__openmp_backend_tag, _ExecutionPolicy&&, _Index __n, _Tp __initial,
+                       _Rp __reduce, _Cp __combine, _Sp __scan, _Ap __apex)
+{
+    if (__n <= __default_chunk_size)
+    {
+        _Tp __sum = __initial;
+        if (__n)
+        {
+            __sum = __combine(__sum, __reduce(_Index(0), __n));
+        }
+        __apex(__sum);
+        if (__n)
+        {
+            __scan(_Index(0), __n, __initial);
+        }
+        return;
+    }
+
+    if (omp_in_parallel())
+    {
+        __pstl::__omp_backend::__parallel_strict_scan_body<_ExecutionPolicy>(__n, __initial, __reduce, __combine,
+                                                                             __scan, __apex);
+    }
+    else
+    {
+        _PSTL_PRAGMA(omp parallel)
+        _PSTL_PRAGMA(omp single nowait)
+        {
+            __pstl::__omp_backend::__parallel_strict_scan_body<_ExecutionPolicy>(__n, __initial, __reduce, __combine,
+                                                                                 __scan, __apex);
+        }
+    }
+}
+
+} // namespace __omp_backend
+} // namespace __pstl
+#endif // _PSTL_INTERNAL_OMP_PARALLEL_SCAN_H
diff --git a/pstl/include/pstl/internal/omp/parallel_stable_partial_sort.h b/pstl/include/pstl/internal/omp/parallel_stable_partial_sort.h
new file mode 100644
index 0000000..06cd55b
--- /dev/null
+++ b/pstl/include/pstl/internal/omp/parallel_stable_partial_sort.h
@@ -0,0 +1,33 @@
+// -*- C++ -*-
+// -*-===----------------------------------------------------------------------===//
+//
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_INTERNAL_OMP_PARALLEL_STABLE_PARTIAL_SORT_H
+#define _PSTL_INTERNAL_OMP_PARALLEL_STABLE_PARTIAL_SORT_H
+
+#include "util.h"
+
+namespace __pstl
+{
+namespace __omp_backend
+{
+
+template <typename _RandomAccessIterator, typename _Compare, typename _LeafSort>
+void
+__parallel_stable_partial_sort(__pstl::__internal::__openmp_backend_tag, _RandomAccessIterator __xs,
+                               _RandomAccessIterator __xe, _Compare __comp, _LeafSort __leaf_sort,
+                               std::size_t /* __nsort */)
+{
+    // TODO: "Parallel partial sort needs to be implemented.");
+    __leaf_sort(__xs, __xe, __comp);
+}
+
+} // namespace __omp_backend
+} // namespace __pstl
+#endif // _PSTL_INTERNAL_OMP_PARALLEL_STABLE_PARTIAL_SORT_H
diff --git a/pstl/include/pstl/internal/omp/parallel_stable_sort.h b/pstl/include/pstl/internal/omp/parallel_stable_sort.h
new file mode 100644
index 0000000..e4d0676
--- /dev/null
+++ b/pstl/include/pstl/internal/omp/parallel_stable_sort.h
@@ -0,0 +1,160 @@
+// -*- C++ -*-
+// -*-===----------------------------------------------------------------------===//
+//
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_INTERNAL_OMP_PARALLEL_STABLE_SORT_H
+#define _PSTL_INTERNAL_OMP_PARALLEL_STABLE_SORT_H
+
+#include "util.h"
+#include "parallel_merge.h"
+
+namespace __pstl
+{
+namespace __omp_backend
+{
+
+namespace __sort_details
+{
+struct __move_value
+{
+    template <typename _Iterator, typename _OutputIterator>
+    void
+    operator()(_Iterator __x, _OutputIterator __z) const
+    {
+        *__z = std::move(*__x);
+    }
+};
+
+template <typename _RandomAccessIterator, typename _OutputIterator>
+_OutputIterator
+__parallel_move_range(_RandomAccessIterator __first1, _RandomAccessIterator __last1, _OutputIterator __d_first)
+{
+    std::size_t __size = __last1 - __first1;
+
+    // Perform serial moving of small chunks
+
+    if (__size <= __default_chunk_size)
+    {
+        return std::move(__first1, __last1, __d_first);
+    }
+
+    // Perform parallel moving of larger chunks
+    auto __policy = __pstl::__omp_backend::__chunk_partitioner(__first1, __last1);
+
+    _PSTL_PRAGMA(omp taskloop)
+    for (std::size_t __chunk = 0; __chunk < __policy.__n_chunks; ++__chunk)
+    {
+        __pstl::__omp_backend::__process_chunk(__policy, __first1, __chunk,
+                                       [&](auto __chunk_first, auto __chunk_last)
+                                       {
+                                           auto __chunk_offset = __chunk_first - __first1;
+                                           auto __output_it = __d_first + __chunk_offset;
+                                           std::move(__chunk_first, __chunk_last, __output_it);
+                                       });
+    }
+
+    return __d_first + __size;
+}
+
+struct __move_range
+{
+    template <typename _RandomAccessIterator, typename _OutputIterator>
+    _OutputIterator
+    operator()(_RandomAccessIterator __first1, _RandomAccessIterator __last1, _OutputIterator __d_first) const
+    {
+        return __pstl::__omp_backend::__sort_details::__parallel_move_range(__first1, __last1, __d_first);
+    }
+};
+} // namespace __sort_details
+
+template <typename _RandomAccessIterator, typename _Compare, typename _LeafSort>
+void
+__parallel_stable_sort_body(_RandomAccessIterator __xs, _RandomAccessIterator __xe, _Compare __comp,
+                            _LeafSort __leaf_sort)
+{
+    using _ValueType = typename std::iterator_traits<_RandomAccessIterator>::value_type;
+    using _VecType = typename std::vector<_ValueType>;
+    using _OutputIterator = typename _VecType::iterator;
+    using _MoveValue = typename __omp_backend::__sort_details::__move_value;
+    using _MoveRange = __omp_backend::__sort_details::__move_range;
+
+    if (__should_run_serial(__xs, __xe))
+    {
+        __leaf_sort(__xs, __xe, __comp);
+    }
+    else
+    {
+        std::size_t __size = __xe - __xs;
+        auto __mid = __xs + (__size / 2);
+        __pstl::__omp_backend::__parallel_invoke_body(
+            [&]() { __parallel_stable_sort_body(__xs, __mid, __comp, __leaf_sort); },
+            [&]() { __parallel_stable_sort_body(__mid, __xe, __comp, __leaf_sort); });
+
+        // Perform a parallel merge of the sorted ranges into __output_data.
+        _VecType __output_data(__size);
+        _MoveValue __move_value;
+        _MoveRange __move_range;
+        __utils::__serial_move_merge __merge(__size);
+        __pstl::__omp_backend::__parallel_merge_body(
+            __mid - __xs, __xe - __mid, __xs, __mid, __mid, __xe, __output_data.begin(), __comp,
+            [&__merge, &__move_value, &__move_range](_RandomAccessIterator __as, _RandomAccessIterator __ae,
+                                                     _RandomAccessIterator __bs, _RandomAccessIterator __be,
+                                                     _OutputIterator __cs, _Compare __comp)
+            { __merge(__as, __ae, __bs, __be, __cs, __comp, __move_value, __move_value, __move_range, __move_range); });
+
+        // Move the values from __output_data back in the original source range.
+        __pstl::__omp_backend::__sort_details::__parallel_move_range(__output_data.begin(), __output_data.end(), __xs);
+    }
+}
+
+template <class _ExecutionPolicy, typename _RandomAccessIterator, typename _Compare, typename _LeafSort>
+void
+__parallel_stable_sort(__pstl::__internal::__openmp_backend_tag __tag, _ExecutionPolicy&& /*__exec*/,
+                       _RandomAccessIterator __xs, _RandomAccessIterator __xe, _Compare __comp, _LeafSort __leaf_sort,
+                       std::size_t __nsort = 0)
+{
+    auto __count = static_cast<std::size_t>(__xe - __xs);
+    if (__count <= __default_chunk_size || __nsort < __count)
+    {
+        __leaf_sort(__xs, __xe, __comp);
+        return;
+    }
+
+    // TODO: the partial sort implementation should
+    // be shared with the other backends.
+
+    if (omp_in_parallel())
+    {
+        if (__count <= __nsort)
+        {
+            __pstl::__omp_backend::__parallel_stable_sort_body(__xs, __xe, __comp, __leaf_sort);
+        }
+        else
+        {
+            __pstl::__omp_backend::__parallel_stable_partial_sort(__tag, __xs, __xe, __comp, __leaf_sort, __nsort);
+        }
+    }
+    else
+    {
+        _PSTL_PRAGMA(omp parallel)
+        _PSTL_PRAGMA(omp single nowait)
+        if (__count <= __nsort)
+        {
+            __pstl::__omp_backend::__parallel_stable_sort_body(__xs, __xe, __comp, __leaf_sort);
+        }
+        else
+        {
+            __pstl::__omp_backend::__parallel_stable_partial_sort(__tag, __xs, __xe, __comp, __leaf_sort, __nsort);
+        }
+    }
+}
+
+} // namespace __omp_backend
+} // namespace __pstl
+#endif // _PSTL_INTERNAL_OMP_PARALLEL_STABLE_SORT_H
diff --git a/pstl/include/pstl/internal/omp/parallel_transform_reduce.h b/pstl/include/pstl/internal/omp/parallel_transform_reduce.h
new file mode 100644
index 0000000..1d4cc0a
--- /dev/null
+++ b/pstl/include/pstl/internal/omp/parallel_transform_reduce.h
@@ -0,0 +1,113 @@
+// -*- C++ -*-
+// -*-===----------------------------------------------------------------------===//
+//
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_INTERNAL_OMP_PARALLEL_TRANSFORM_REDUCE_H
+#define _PSTL_INTERNAL_OMP_PARALLEL_TRANSFORM_REDUCE_H
+
+#include "util.h"
+
+namespace __pstl
+{
+namespace __omp_backend
+{
+
+//------------------------------------------------------------------------
+// parallel_transform_reduce
+//
+// Notation:
+//      r(i,j,init) returns reduction of init with reduction over [i,j)
+//      u(i) returns f(i,i+1,identity) for a hypothetical left identity element
+//      of r c(x,y) combines values x and y that were the result of r or u
+//------------------------------------------------------------------------
+
+template <class _RandomAccessIterator, class _UnaryOp, class _Value, class _Combiner, class _Reduction>
+auto
+__transform_reduce_body(_RandomAccessIterator __first, _RandomAccessIterator __last, _UnaryOp __unary_op, _Value __init,
+                        _Combiner __combiner, _Reduction __reduction)
+{
+    const std::size_t __num_threads = omp_get_num_threads();
+    const std::size_t __size = __last - __first;
+
+    // Initial partition of the iteration space into chunks. If the range is too small,
+    // this will result in a nonsense policy, so we check on the size as well below.
+    auto __policy = __omp_backend::__chunk_partitioner(__first + __num_threads, __last);
+
+    if (__size <= __num_threads || __policy.__n_chunks < 2)
+    {
+        return __reduction(__first, __last, __init);
+    }
+
+    // Here, we cannot use OpenMP UDR because we must store the init value in
+    // the combiner and it will be used several times. Although there should be
+    // the only one; we manually generate the identity elements for each thread.
+    std::vector<_Value> __accums;
+    __accums.reserve(__num_threads);
+
+    // initialize accumulators for all threads
+    for (std::size_t __i = 0; __i < __num_threads; ++__i)
+    {
+        __accums.emplace_back(__unary_op(__first + __i));
+    }
+
+    // main loop
+    _PSTL_PRAGMA(omp taskloop shared(__accums))
+    for (std::size_t __chunk = 0; __chunk < __policy.__n_chunks; ++__chunk)
+    {
+        __pstl::__omp_backend::__process_chunk(__policy, __first + __num_threads, __chunk,
+                                       [&](auto __chunk_first, auto __chunk_last)
+                                       {
+                                           auto __thread_num = omp_get_thread_num();
+                                           __accums[__thread_num] =
+                                               __reduction(__chunk_first, __chunk_last, __accums[__thread_num]);
+                                       });
+    }
+
+    // combine by accumulators
+    for (std::size_t __i = 0; __i < __num_threads; ++__i)
+    {
+        __init = __combiner(__init, __accums[__i]);
+    }
+
+    return __init;
+}
+
+template <class _ExecutionPolicy, class _RandomAccessIterator, class _UnaryOp, class _Value, class _Combiner,
+          class _Reduction>
+_Value
+__parallel_transform_reduce(__pstl::__internal::__openmp_backend_tag, _ExecutionPolicy&&, _RandomAccessIterator __first,
+                            _RandomAccessIterator __last, _UnaryOp __unary_op, _Value __init, _Combiner __combiner,
+                            _Reduction __reduction)
+{
+    _Value __result = __init;
+    if (omp_in_parallel())
+    {
+        // We don't create a nested parallel region in an existing parallel
+        // region: just create tasks
+        __result = __pstl::__omp_backend::__transform_reduce_body(__first, __last, __unary_op, __init, __combiner,
+                                                                  __reduction);
+    }
+    else
+    {
+        // Create a parallel region, and a single thread will create tasks
+        // for the region.
+        _PSTL_PRAGMA(omp parallel)
+        _PSTL_PRAGMA(omp single nowait)
+        {
+            __result = __pstl::__omp_backend::__transform_reduce_body(__first, __last, __unary_op, __init, __combiner,
+                                                                      __reduction);
+        }
+    }
+
+    return __result;
+}
+
+} // namespace __omp_backend
+} // namespace __pstl
+#endif // _PSTL_INTERNAL_OMP_PARALLEL_TRANSFORM_REDUCE_H
diff --git a/pstl/include/pstl/internal/omp/parallel_transform_scan.h b/pstl/include/pstl/internal/omp/parallel_transform_scan.h
new file mode 100644
index 0000000..f836289
--- /dev/null
+++ b/pstl/include/pstl/internal/omp/parallel_transform_scan.h
@@ -0,0 +1,32 @@
+// -*- C++ -*-
+// -*-===----------------------------------------------------------------------===//
+//
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_INTERNAL_OMP_PARALLEL_TRANSFORM_SCAN_H
+#define _PSTL_INTERNAL_OMP_PARALLEL_TRANSFORM_SCAN_H
+
+#include "util.h"
+
+namespace __pstl
+{
+namespace __omp_backend
+{
+
+template <class _ExecutionPolicy, class _Index, class _Up, class _Tp, class _Cp, class _Rp, class _Sp>
+_Tp
+__parallel_transform_scan(__pstl::__internal::__openmp_backend_tag, _ExecutionPolicy&&, _Index __n, _Up /* __u */,
+                          _Tp __init, _Cp /* __combine */, _Rp /* __brick_reduce */, _Sp __scan)
+{
+    // TODO: parallelize this function.
+    return __scan(_Index(0), __n, __init);
+}
+
+} // namespace __omp_backend
+} // namespace __pstl
+#endif // _PSTL_INTERNAL_OMP_PARALLEL_TRANSFORM_SCAN_H
diff --git a/pstl/include/pstl/internal/omp/util.h b/pstl/include/pstl/internal/omp/util.h
new file mode 100644
index 0000000..c88d980
--- /dev/null
+++ b/pstl/include/pstl/internal/omp/util.h
@@ -0,0 +1,173 @@
+// -*- C++ -*-
+// -*-===----------------------------------------------------------------------===//
+//
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_INTERNAL_OMP_UTIL_H
+#define _PSTL_INTERNAL_OMP_UTIL_H
+
+#include <algorithm>
+#include <atomic>
+#include <iterator>
+#include <cstddef>
+#include <cstdio>
+#include <memory>
+#include <vector>
+#include <omp.h>
+
+#include "../parallel_backend_utils.h"
+#include "../unseq_backend_simd.h"
+#include "../utils.h"
+
+// Portability "#pragma" definition
+#ifdef _MSC_VER
+#    define _PSTL_PRAGMA(x) __pragma(x)
+#else
+#    define _PSTL_PRAGMA(x) _Pragma(#    x)
+#endif
+
+_PSTL_HIDE_FROM_ABI_PUSH
+
+namespace __pstl
+{
+namespace __omp_backend
+{
+
+//------------------------------------------------------------------------
+// use to cancel execution
+//------------------------------------------------------------------------
+inline void
+__cancel_execution()
+{
+    // TODO: Figure out how to make cancelation work.
+}
+
+//------------------------------------------------------------------------
+// raw buffer
+//------------------------------------------------------------------------
+
+template <typename _Tp>
+class __buffer
+{
+    std::allocator<_Tp> __allocator_;
+    _Tp* __ptr_;
+    const std::size_t __buf_size_;
+    __buffer(const __buffer&) = delete;
+    void
+    operator=(const __buffer&) = delete;
+
+  public:
+    __buffer(std::size_t __n) : __allocator_(), __ptr_(__allocator_.allocate(__n)), __buf_size_(__n) {}
+
+    operator bool() const { return __ptr_ != nullptr; }
+
+    _Tp*
+    get() const
+    {
+        return __ptr_;
+    }
+    ~__buffer() { __allocator_.deallocate(__ptr_, __buf_size_); }
+};
+
+// Preliminary size of each chunk: requires further discussion
+inline constexpr std::size_t __default_chunk_size = 2048;
+
+// Convenience function to determine when we should run serial.
+template <typename _Iterator, std::enable_if_t<!std::is_integral<_Iterator>::value, bool> = true>
+constexpr auto
+__should_run_serial(_Iterator __first, _Iterator __last) -> bool
+{
+    using _difference_type = typename std::iterator_traits<_Iterator>::difference_type;
+    auto __size = std::distance(__first, __last);
+    return __size <= static_cast<_difference_type>(__default_chunk_size);
+}
+
+template <typename _Index, std::enable_if_t<std::is_integral<_Index>::value, bool> = true>
+constexpr auto
+__should_run_serial(_Index __first, _Index __last) -> bool
+{
+    using _difference_type = _Index;
+    auto __size = __last - __first;
+    return __size <= static_cast<_difference_type>(__default_chunk_size);
+}
+
+struct __chunk_metrics
+{
+    std::size_t __n_chunks;
+    std::size_t __chunk_size;
+    std::size_t __first_chunk_size;
+};
+
+// The iteration space partitioner according to __requested_chunk_size
+template <class _RandomAccessIterator, class _Size = std::size_t>
+auto
+__chunk_partitioner(_RandomAccessIterator __first, _RandomAccessIterator __last,
+                    _Size __requested_chunk_size = __default_chunk_size) -> __chunk_metrics
+{
+    /*
+     * This algorithm improves distribution of elements in chunks by avoiding
+     * small tail chunks. The leftover elements that do not fit neatly into
+     * the chunk size are redistributed to early chunks. This improves
+     * utilization of the processor's prefetch and reduces the number of
+     * tasks needed by 1.
+     */
+
+    const _Size __n = __last - __first;
+    _Size __n_chunks = 0;
+    _Size __chunk_size = 0;
+    _Size __first_chunk_size = 0;
+    if (__n < __requested_chunk_size)
+    {
+        __chunk_size = __n;
+        __first_chunk_size = __n;
+        __n_chunks = 1;
+        return __chunk_metrics{__n_chunks, __chunk_size, __first_chunk_size};
+    }
+
+    __n_chunks = (__n / __requested_chunk_size) + 1;
+    __chunk_size = __n / __n_chunks;
+    __first_chunk_size = __chunk_size;
+    const _Size __n_leftover_items = __n - (__n_chunks * __chunk_size);
+
+    if (__n_leftover_items == __chunk_size)
+    {
+        __n_chunks += 1;
+        return __chunk_metrics{__n_chunks, __chunk_size, __first_chunk_size};
+    }
+    else if (__n_leftover_items == 0)
+    {
+        __first_chunk_size = __chunk_size;
+        return __chunk_metrics{__n_chunks, __chunk_size, __first_chunk_size};
+    }
+
+    const _Size __n_extra_items_per_chunk = __n_leftover_items / __n_chunks;
+    const _Size __n_final_leftover_items = __n_leftover_items - (__n_extra_items_per_chunk * __n_chunks);
+
+    __chunk_size += __n_extra_items_per_chunk;
+    __first_chunk_size = __chunk_size + __n_final_leftover_items;
+
+    return __chunk_metrics{__n_chunks, __chunk_size, __first_chunk_size};
+}
+
+template <typename _Iterator, typename _Index, typename _Func>
+void
+__process_chunk(const __chunk_metrics& __metrics, _Iterator __base, _Index __chunk_index, _Func __f)
+{
+    auto __this_chunk_size = __chunk_index == 0 ? __metrics.__first_chunk_size : __metrics.__chunk_size;
+    auto __index = __chunk_index == 0 ? 0
+                                      : (__chunk_index * __metrics.__chunk_size) +
+                                            (__metrics.__first_chunk_size - __metrics.__chunk_size);
+    auto __first = __base + __index;
+    auto __last = __first + __this_chunk_size;
+    __f(__first, __last);
+}
+
+} // namespace __omp_backend
+} // namespace __pstl
+
+#endif // _PSTL_INTERNAL_OMP_UTIL_H
diff --git a/pstl/include/pstl/internal/parallel_backend.h b/pstl/include/pstl/internal/parallel_backend.h
new file mode 100644
index 0000000..4da871b
--- /dev/null
+++ b/pstl/include/pstl/internal/parallel_backend.h
@@ -0,0 +1,37 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_PARALLEL_BACKEND_H
+#define _PSTL_PARALLEL_BACKEND_H
+
+#include "pstl_config.h"
+
+#if defined(_PSTL_PAR_BACKEND_SERIAL)
+#    include "parallel_backend_serial.h"
+namespace __pstl
+{
+namespace __par_backend = __serial_backend;
+}
+#elif defined(_PSTL_PAR_BACKEND_TBB)
+#    include "parallel_backend_tbb.h"
+namespace __pstl
+{
+namespace __par_backend = __tbb_backend;
+}
+#elif defined(_PSTL_PAR_BACKEND_OPENMP)
+#    include "parallel_backend_omp.h"
+namespace __pstl
+{
+namespace __par_backend = __omp_backend;
+}
+#else
+_PSTL_PRAGMA_MESSAGE("Parallel backend was not specified");
+#endif
+
+#endif /* _PSTL_PARALLEL_BACKEND_H */
diff --git a/pstl/include/pstl/internal/parallel_backend_omp.h b/pstl/include/pstl/internal/parallel_backend_omp.h
new file mode 100644
index 0000000..7398cfe
--- /dev/null
+++ b/pstl/include/pstl/internal/parallel_backend_omp.h
@@ -0,0 +1,58 @@
+// -*- C++ -*-
+// -*-===----------------------------------------------------------------------===//
+//
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_PARALLEL_BACKEND_OMP_H
+#define _PSTL_PARALLEL_BACKEND_OMP_H
+
+//------------------------------------------------------------------------
+// parallel_invoke
+//------------------------------------------------------------------------
+
+#include "./omp/parallel_invoke.h"
+
+//------------------------------------------------------------------------
+// parallel_for
+//------------------------------------------------------------------------
+
+#include "./omp/parallel_for.h"
+
+//------------------------------------------------------------------------
+// parallel_for_each
+//------------------------------------------------------------------------
+
+#include "./omp/parallel_for_each.h"
+
+//------------------------------------------------------------------------
+// parallel_reduce
+//------------------------------------------------------------------------
+
+#include "./omp/parallel_reduce.h"
+#include "./omp/parallel_transform_reduce.h"
+
+//------------------------------------------------------------------------
+// parallel_scan
+//------------------------------------------------------------------------
+
+#include "./omp/parallel_scan.h"
+#include "./omp/parallel_transform_scan.h"
+
+//------------------------------------------------------------------------
+// parallel_stable_sort
+//------------------------------------------------------------------------
+
+#include "./omp/parallel_stable_partial_sort.h"
+#include "./omp/parallel_stable_sort.h"
+
+//------------------------------------------------------------------------
+// parallel_merge
+//------------------------------------------------------------------------
+#include "./omp/parallel_merge.h"
+
+#endif //_PSTL_PARALLEL_BACKEND_OMP_H
diff --git a/pstl/include/pstl/internal/parallel_backend_serial.h b/pstl/include/pstl/internal/parallel_backend_serial.h
new file mode 100644
index 0000000..ad2c5fc
--- /dev/null
+++ b/pstl/include/pstl/internal/parallel_backend_serial.h
@@ -0,0 +1,137 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_PARALLEL_BACKEND_SERIAL_H
+#define _PSTL_PARALLEL_BACKEND_SERIAL_H
+
+#include <algorithm>
+#include <cstddef>
+#include <memory>
+#include <numeric>
+#include <utility>
+
+#include "pstl_config.h"
+
+_PSTL_HIDE_FROM_ABI_PUSH
+
+namespace __pstl
+{
+namespace __serial_backend
+{
+
+template <typename _Tp>
+class __buffer
+{
+    std::allocator<_Tp> __allocator_;
+    _Tp* __ptr_;
+    const std::size_t __buf_size_;
+    __buffer(const __buffer&) = delete;
+    void
+    operator=(const __buffer&) = delete;
+
+  public:
+    __buffer(std::size_t __n) : __allocator_(), __ptr_(__allocator_.allocate(__n)), __buf_size_(__n) {}
+
+    operator bool() const { return __ptr_ != nullptr; }
+    _Tp*
+    get() const
+    {
+        return __ptr_;
+    }
+    ~__buffer() { __allocator_.deallocate(__ptr_, __buf_size_); }
+};
+
+inline void
+__cancel_execution()
+{
+}
+
+template <class _ExecutionPolicy, class _Index, class _Fp>
+void
+__parallel_for(__pstl::__internal::__serial_backend_tag, _ExecutionPolicy&&, _Index __first, _Index __last, _Fp __f)
+{
+    __f(__first, __last);
+}
+
+template <class _ExecutionPolicy, class _Value, class _Index, typename _RealBody, typename _Reduction>
+_Value
+__parallel_reduce(__pstl::__internal::__serial_backend_tag, _ExecutionPolicy&&, _Index __first, _Index __last,
+                  const _Value& __identity, const _RealBody& __real_body, const _Reduction&)
+{
+    if (__first == __last)
+    {
+        return __identity;
+    }
+    else
+    {
+        return __real_body(__first, __last, __identity);
+    }
+}
+
+template <class _ExecutionPolicy, class _Index, class _UnaryOp, class _Tp, class _BinaryOp, class _Reduce>
+_Tp
+__parallel_transform_reduce(__pstl::__internal::__serial_backend_tag, _ExecutionPolicy&&, _Index __first, _Index __last,
+                            _UnaryOp, _Tp __init, _BinaryOp, _Reduce __reduce)
+{
+    return __reduce(__first, __last, __init);
+}
+
+template <class _ExecutionPolicy, typename _Index, typename _Tp, typename _Rp, typename _Cp, typename _Sp, typename _Ap>
+void
+__parallel_strict_scan(__pstl::__internal::__serial_backend_tag, _ExecutionPolicy&&, _Index __n, _Tp __initial,
+                       _Rp __reduce, _Cp __combine, _Sp __scan, _Ap __apex)
+{
+    _Tp __sum = __initial;
+    if (__n)
+        __sum = __combine(__sum, __reduce(_Index(0), __n));
+    __apex(__sum);
+    if (__n)
+        __scan(_Index(0), __n, __initial);
+}
+
+template <class _ExecutionPolicy, class _Index, class _UnaryOp, class _Tp, class _BinaryOp, class _Reduce, class _Scan>
+_Tp
+__parallel_transform_scan(__pstl::__internal::__serial_backend_tag, _ExecutionPolicy&&, _Index __n, _UnaryOp,
+                          _Tp __init, _BinaryOp, _Reduce, _Scan __scan)
+{
+    return __scan(_Index(0), __n, __init);
+}
+
+template <class _ExecutionPolicy, typename _RandomAccessIterator, typename _Compare, typename _LeafSort>
+void
+__parallel_stable_sort(__pstl::__internal::__serial_backend_tag, _ExecutionPolicy&&, _RandomAccessIterator __first,
+                       _RandomAccessIterator __last, _Compare __comp, _LeafSort __leaf_sort, std::size_t = 0)
+{
+    __leaf_sort(__first, __last, __comp);
+}
+
+template <class _ExecutionPolicy, typename _RandomAccessIterator1, typename _RandomAccessIterator2,
+          typename _RandomAccessIterator3, typename _Compare, typename _LeafMerge>
+void
+__parallel_merge(__pstl::__internal::__serial_backend_tag, _ExecutionPolicy&&, _RandomAccessIterator1 __first1,
+                 _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2,
+                 _RandomAccessIterator3 __outit, _Compare __comp, _LeafMerge __leaf_merge)
+{
+    __leaf_merge(__first1, __last1, __first2, __last2, __outit, __comp);
+}
+
+template <class _ExecutionPolicy, typename _F1, typename _F2>
+void
+__parallel_invoke(__pstl::__internal::__serial_backend_tag, _ExecutionPolicy&&, _F1&& __f1, _F2&& __f2)
+{
+    std::forward<_F1>(__f1)();
+    std::forward<_F2>(__f2)();
+}
+
+} // namespace __serial_backend
+} // namespace __pstl
+
+_PSTL_HIDE_FROM_ABI_POP
+
+#endif /* _PSTL_PARALLEL_BACKEND_SERIAL_H */
diff --git a/pstl/include/pstl/internal/parallel_backend_tbb.h b/pstl/include/pstl/internal/parallel_backend_tbb.h
new file mode 100644
index 0000000..e336f69
--- /dev/null
+++ b/pstl/include/pstl/internal/parallel_backend_tbb.h
@@ -0,0 +1,1296 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_PARALLEL_BACKEND_TBB_H
+#define _PSTL_PARALLEL_BACKEND_TBB_H
+
+#include <algorithm>
+#include <type_traits>
+
+#include "pstl_config.h"
+#include "parallel_backend_utils.h"
+
+// Bring in minimal required subset of Intel TBB
+#include <tbb/blocked_range.h>
+#include <tbb/parallel_for.h>
+#include <tbb/parallel_reduce.h>
+#include <tbb/parallel_scan.h>
+#include <tbb/parallel_invoke.h>
+#include <tbb/task_arena.h>
+#include <tbb/tbb_allocator.h>
+#include <tbb/task.h>
+
+#if TBB_INTERFACE_VERSION < 10000
+#    error Intel(R) Threading Building Blocks 2018 is required; older versions are not supported.
+#endif
+
+_PSTL_HIDE_FROM_ABI_PUSH
+
+namespace __pstl
+{
+namespace __tbb_backend
+{
+
+//! Raw memory buffer with automatic freeing and no exceptions.
+/** Some of our algorithms need to start with raw memory buffer,
+not an initialize array, because initialization/destruction
+would make the span be at least O(N). */
+// tbb::allocator can improve performance in some cases.
+template <typename _Tp>
+class __buffer
+{
+    tbb::tbb_allocator<_Tp> _M_allocator;
+    _Tp* _M_ptr;
+    const std::size_t _M_buf_size;
+    __buffer(const __buffer&) = delete;
+    void
+    operator=(const __buffer&) = delete;
+
+  public:
+    //! Try to obtain buffer of given size to store objects of _Tp type
+    __buffer(std::size_t n) : _M_allocator(), _M_ptr(_M_allocator.allocate(n)), _M_buf_size(n) {}
+    //! True if buffer was successfully obtained, zero otherwise.
+    operator bool() const { return _M_ptr != NULL; }
+    //! Return pointer to buffer, or  NULL if buffer could not be obtained.
+    _Tp*
+    get() const
+    {
+        return _M_ptr;
+    }
+    //! Destroy buffer
+    ~__buffer() { _M_allocator.deallocate(_M_ptr, _M_buf_size); }
+};
+
+// Wrapper for tbb::task
+inline void
+__cancel_execution()
+{
+#if TBB_INTERFACE_VERSION <= 12000
+    tbb::task::self().group()->cancel_group_execution();
+#else
+    tbb::task::current_context()->cancel_group_execution();
+#endif
+}
+
+//------------------------------------------------------------------------
+// parallel_for
+//------------------------------------------------------------------------
+
+template <class _Index, class _RealBody>
+class __parallel_for_body
+{
+  public:
+    __parallel_for_body(const _RealBody& __body) : _M_body(__body) {}
+    __parallel_for_body(const __parallel_for_body& __body) : _M_body(__body._M_body) {}
+    void
+    operator()(const tbb::blocked_range<_Index>& __range) const
+    {
+        _M_body(__range.begin(), __range.end());
+    }
+
+  private:
+    _RealBody _M_body;
+};
+
+//! Evaluation of brick f[i,j) for each subrange [i,j) of [first,last)
+// wrapper over tbb::parallel_for
+template <class _ExecutionPolicy, class _Index, class _Fp>
+void
+__parallel_for(__pstl::__internal::__tbb_backend_tag, _ExecutionPolicy&&, _Index __first, _Index __last, _Fp __f)
+{
+    tbb::this_task_arena::isolate([=]() {
+        tbb::parallel_for(tbb::blocked_range<_Index>(__first, __last), __parallel_for_body<_Index, _Fp>(__f));
+    });
+}
+
+//! Evaluation of brick f[i,j) for each subrange [i,j) of [first,last)
+// wrapper over tbb::parallel_reduce
+template <class _ExecutionPolicy, class _Value, class _Index, typename _RealBody, typename _Reduction>
+_Value
+__parallel_reduce(__pstl::__internal::__tbb_backend_tag, _ExecutionPolicy&&, _Index __first, _Index __last,
+                  const _Value& __identity, const _RealBody& __real_body, const _Reduction& __reduction)
+{
+    return tbb::this_task_arena::isolate([__first, __last, &__identity, &__real_body, &__reduction]() -> _Value {
+        return tbb::parallel_reduce(
+            tbb::blocked_range<_Index>(__first, __last), __identity,
+            [__real_body](const tbb::blocked_range<_Index>& __r, const _Value& __value) -> _Value {
+                return __real_body(__r.begin(), __r.end(), __value);
+            },
+            __reduction);
+    });
+}
+
+//------------------------------------------------------------------------
+// parallel_transform_reduce
+//
+// Notation:
+//      r(i,j,init) returns reduction of init with reduction over [i,j)
+//      u(i) returns f(i,i+1,identity) for a hypothetical left identity element of r
+//      c(x,y) combines values x and y that were the result of r or u
+//------------------------------------------------------------------------
+
+template <class _Index, class _Up, class _Tp, class _Cp, class _Rp>
+struct __par_trans_red_body
+{
+    alignas(_Tp) char _M_sum_storage[sizeof(_Tp)]; // Holds generalized non-commutative sum when has_sum==true
+    _Rp _M_brick_reduce;                           // Most likely to have non-empty layout
+    _Up _M_u;
+    _Cp _M_combine;
+    bool _M_has_sum; // Put last to minimize size of class
+    _Tp&
+    sum()
+    {
+        __TBB_ASSERT(_M_has_sum, "sum expected");
+        return *(_Tp*)_M_sum_storage;
+    }
+    __par_trans_red_body(_Up __u, _Tp __init, _Cp __c, _Rp __r)
+        : _M_brick_reduce(__r), _M_u(__u), _M_combine(__c), _M_has_sum(true)
+    {
+        new (_M_sum_storage) _Tp(__init);
+    }
+
+    __par_trans_red_body(__par_trans_red_body& __left, tbb::split)
+        : _M_brick_reduce(__left._M_brick_reduce), _M_u(__left._M_u), _M_combine(__left._M_combine), _M_has_sum(false)
+    {
+    }
+
+    ~__par_trans_red_body()
+    {
+        // 17.6.5.12 tells us to not worry about catching exceptions from destructors.
+        if (_M_has_sum)
+            sum().~_Tp();
+    }
+
+    void
+    join(__par_trans_red_body& __rhs)
+    {
+        sum() = _M_combine(sum(), __rhs.sum());
+    }
+
+    void
+    operator()(const tbb::blocked_range<_Index>& __range)
+    {
+        _Index __i = __range.begin();
+        _Index __j = __range.end();
+        if (!_M_has_sum)
+        {
+            __TBB_ASSERT(__range.size() > 1, "there should be at least 2 elements");
+            new (&_M_sum_storage)
+                _Tp(_M_combine(_M_u(__i), _M_u(__i + 1))); // The condition i+1 < j is provided by the grain size of 3
+            _M_has_sum = true;
+            std::advance(__i, 2);
+            if (__i == __j)
+                return;
+        }
+        sum() = _M_brick_reduce(__i, __j, sum());
+    }
+};
+
+template <class _ExecutionPolicy, class _Index, class _Up, class _Tp, class _Cp, class _Rp>
+_Tp
+__parallel_transform_reduce(__pstl::__internal::__tbb_backend_tag, _ExecutionPolicy&&, _Index __first, _Index __last,
+                            _Up __u, _Tp __init, _Cp __combine, _Rp __brick_reduce)
+{
+    __tbb_backend::__par_trans_red_body<_Index, _Up, _Tp, _Cp, _Rp> __body(__u, __init, __combine, __brick_reduce);
+    // The grain size of 3 is used in order to provide mininum 2 elements for each body
+    tbb::this_task_arena::isolate(
+        [__first, __last, &__body]() { tbb::parallel_reduce(tbb::blocked_range<_Index>(__first, __last, 3), __body); });
+    return __body.sum();
+}
+
+//------------------------------------------------------------------------
+// parallel_scan
+//------------------------------------------------------------------------
+
+template <class _Index, class _Up, class _Tp, class _Cp, class _Rp, class _Sp>
+class __trans_scan_body
+{
+    alignas(_Tp) char _M_sum_storage[sizeof(_Tp)]; // Holds generalized non-commutative sum when has_sum==true
+    _Rp _M_brick_reduce;                           // Most likely to have non-empty layout
+    _Up _M_u;
+    _Cp _M_combine;
+    _Sp _M_scan;
+    bool _M_has_sum; // Put last to minimize size of class
+  public:
+    __trans_scan_body(_Up __u, _Tp __init, _Cp __combine, _Rp __reduce, _Sp __scan)
+        : _M_brick_reduce(__reduce), _M_u(__u), _M_combine(__combine), _M_scan(__scan), _M_has_sum(true)
+    {
+        new (_M_sum_storage) _Tp(__init);
+    }
+
+    __trans_scan_body(__trans_scan_body& __b, tbb::split)
+        : _M_brick_reduce(__b._M_brick_reduce), _M_u(__b._M_u), _M_combine(__b._M_combine), _M_scan(__b._M_scan),
+          _M_has_sum(false)
+    {
+    }
+
+    ~__trans_scan_body()
+    {
+        // 17.6.5.12 tells us to not worry about catching exceptions from destructors.
+        if (_M_has_sum)
+            sum().~_Tp();
+    }
+
+    _Tp&
+    sum() const
+    {
+        __TBB_ASSERT(_M_has_sum, "sum expected");
+        return *const_cast<_Tp*>(reinterpret_cast<_Tp const*>(_M_sum_storage));
+    }
+
+    void
+    operator()(const tbb::blocked_range<_Index>& __range, tbb::pre_scan_tag)
+    {
+        _Index __i = __range.begin();
+        _Index __j = __range.end();
+        if (!_M_has_sum)
+        {
+            new (&_M_sum_storage) _Tp(_M_u(__i));
+            _M_has_sum = true;
+            ++__i;
+            if (__i == __j)
+                return;
+        }
+        sum() = _M_brick_reduce(__i, __j, sum());
+    }
+
+    void
+    operator()(const tbb::blocked_range<_Index>& __range, tbb::final_scan_tag)
+    {
+        sum() = _M_scan(__range.begin(), __range.end(), sum());
+    }
+
+    void
+    reverse_join(__trans_scan_body& __a)
+    {
+        if (_M_has_sum)
+        {
+            sum() = _M_combine(__a.sum(), sum());
+        }
+        else
+        {
+            new (&_M_sum_storage) _Tp(__a.sum());
+            _M_has_sum = true;
+        }
+    }
+
+    void
+    assign(__trans_scan_body& __b)
+    {
+        sum() = __b.sum();
+    }
+};
+
+template <typename _Index>
+_Index
+__split(_Index __m)
+{
+    _Index __k = 1;
+    while (2 * __k < __m)
+        __k *= 2;
+    return __k;
+}
+
+//------------------------------------------------------------------------
+// __parallel_strict_scan
+//------------------------------------------------------------------------
+
+template <typename _Index, typename _Tp, typename _Rp, typename _Cp>
+void
+__upsweep(_Index __i, _Index __m, _Index __tilesize, _Tp* __r, _Index __lastsize, _Rp __reduce, _Cp __combine)
+{
+    if (__m == 1)
+        __r[0] = __reduce(__i * __tilesize, __lastsize);
+    else
+    {
+        _Index __k = __split(__m);
+        tbb::parallel_invoke(
+            [=] { __tbb_backend::__upsweep(__i, __k, __tilesize, __r, __tilesize, __reduce, __combine); },
+            [=] {
+                __tbb_backend::__upsweep(__i + __k, __m - __k, __tilesize, __r + __k, __lastsize, __reduce, __combine);
+            });
+        if (__m == 2 * __k)
+            __r[__m - 1] = __combine(__r[__k - 1], __r[__m - 1]);
+    }
+}
+
+template <typename _Index, typename _Tp, typename _Cp, typename _Sp>
+void
+__downsweep(_Index __i, _Index __m, _Index __tilesize, _Tp* __r, _Index __lastsize, _Tp __initial, _Cp __combine,
+            _Sp __scan)
+{
+    if (__m == 1)
+        __scan(__i * __tilesize, __lastsize, __initial);
+    else
+    {
+        const _Index __k = __split(__m);
+        tbb::parallel_invoke(
+            [=] { __tbb_backend::__downsweep(__i, __k, __tilesize, __r, __tilesize, __initial, __combine, __scan); },
+            // Assumes that __combine never throws.
+            //TODO: Consider adding a requirement for user functors to be constant.
+            [=, &__combine] {
+                __tbb_backend::__downsweep(__i + __k, __m - __k, __tilesize, __r + __k, __lastsize,
+                                           __combine(__initial, __r[__k - 1]), __combine, __scan);
+            });
+    }
+}
+
+// Adapted from Intel(R) Cilk(TM) version from cilkpub.
+// Let i:len denote a counted interval of length n starting at i.  s denotes a generalized-sum value.
+// Expected actions of the functors are:
+//     reduce(i,len) -> s  -- return reduction value of i:len.
+//     combine(s1,s2) -> s -- return merged sum
+//     apex(s) -- do any processing necessary between reduce and scan.
+//     scan(i,len,initial) -- perform scan over i:len starting with initial.
+// The initial range 0:n is partitioned into consecutive subranges.
+// reduce and scan are each called exactly once per subrange.
+// Thus callers can rely upon side effects in reduce.
+// combine must not throw an exception.
+// apex is called exactly once, after all calls to reduce and before all calls to scan.
+// For example, it's useful for allocating a __buffer used by scan but whose size is the sum of all reduction values.
+// T must have a trivial constructor and destructor.
+template <class _ExecutionPolicy, typename _Index, typename _Tp, typename _Rp, typename _Cp, typename _Sp, typename _Ap>
+void
+__parallel_strict_scan(__pstl::__internal::__tbb_backend_tag, _ExecutionPolicy&&, _Index __n, _Tp __initial,
+                       _Rp __reduce, _Cp __combine, _Sp __scan, _Ap __apex)
+{
+    tbb::this_task_arena::isolate([=, &__combine]() {
+        if (__n > 1)
+        {
+            _Index __p = tbb::this_task_arena::max_concurrency();
+            const _Index __slack = 4;
+            _Index __tilesize = (__n - 1) / (__slack * __p) + 1;
+            _Index __m = (__n - 1) / __tilesize;
+            __buffer<_Tp> __buf(__m + 1);
+            _Tp* __r = __buf.get();
+            __tbb_backend::__upsweep(_Index(0), _Index(__m + 1), __tilesize, __r, __n - __m * __tilesize, __reduce,
+                                     __combine);
+
+            // When __apex is a no-op and __combine has no side effects, a good optimizer
+            // should be able to eliminate all code between here and __apex.
+            // Alternatively, provide a default value for __apex that can be
+            // recognized by metaprogramming that conditionlly executes the following.
+            size_t __k = __m + 1;
+            _Tp __t = __r[__k - 1];
+            while ((__k &= __k - 1))
+                __t = __combine(__r[__k - 1], __t);
+            __apex(__combine(__initial, __t));
+            __tbb_backend::__downsweep(_Index(0), _Index(__m + 1), __tilesize, __r, __n - __m * __tilesize, __initial,
+                                       __combine, __scan);
+            return;
+        }
+        // Fewer than 2 elements in sequence, or out of memory.  Handle has single block.
+        _Tp __sum = __initial;
+        if (__n)
+            __sum = __combine(__sum, __reduce(_Index(0), __n));
+        __apex(__sum);
+        if (__n)
+            __scan(_Index(0), __n, __initial);
+    });
+}
+
+template <class _ExecutionPolicy, class _Index, class _Up, class _Tp, class _Cp, class _Rp, class _Sp>
+_Tp
+__parallel_transform_scan(__pstl::__internal::__tbb_backend_tag, _ExecutionPolicy&&, _Index __n, _Up __u, _Tp __init,
+                          _Cp __combine, _Rp __brick_reduce, _Sp __scan)
+{
+    __trans_scan_body<_Index, _Up, _Tp, _Cp, _Rp, _Sp> __body(__u, __init, __combine, __brick_reduce, __scan);
+    auto __range = tbb::blocked_range<_Index>(0, __n);
+    tbb::this_task_arena::isolate([__range, &__body]() { tbb::parallel_scan(__range, __body); });
+    return __body.sum();
+}
+
+//------------------------------------------------------------------------
+// parallel_stable_sort
+//------------------------------------------------------------------------
+
+//------------------------------------------------------------------------
+// stable_sort utilities
+//
+// These are used by parallel implementations but do not depend on them.
+//------------------------------------------------------------------------
+#define _PSTL_MERGE_CUT_OFF 2000
+
+template <typename _Func>
+class __func_task;
+template <typename _Func>
+class __root_task;
+
+#if TBB_INTERFACE_VERSION <= 12000
+class __task : public tbb::task
+{
+  public:
+    template <typename _Fn>
+    __task*
+    make_continuation(_Fn&& __f)
+    {
+        return new (allocate_continuation()) __func_task<typename std::decay<_Fn>::type>(std::forward<_Fn>(__f));
+    }
+
+    template <typename _Fn>
+    __task*
+    make_child_of(__task* parent, _Fn&& __f)
+    {
+        return new (parent->allocate_child()) __func_task<typename std::decay<_Fn>::type>(std::forward<_Fn>(__f));
+    }
+
+    template <typename _Fn>
+    __task*
+    make_additional_child_of(tbb::task* parent, _Fn&& __f)
+    {
+        return new (tbb::task::allocate_additional_child_of(*parent))
+            __func_task<typename std::decay<_Fn>::type>(std::forward<_Fn>(__f));
+    }
+
+    inline void
+    recycle_as_continuation()
+    {
+        tbb::task::recycle_as_continuation();
+    }
+
+    inline void
+    recycle_as_child_of(__task* parent)
+    {
+        tbb::task::recycle_as_child_of(*parent);
+    }
+
+    inline void
+    spawn(__task* __t)
+    {
+        tbb::task::spawn(*__t);
+    }
+
+    template <typename _Fn>
+    static inline void
+    spawn_root_and_wait(__root_task<_Fn>& __root)
+    {
+        tbb::task::spawn_root_and_wait(*__root._M_task);
+    }
+};
+
+template <typename _Func>
+class __func_task : public __task
+{
+    _Func _M_func;
+
+    tbb::task*
+    execute()
+    {
+        return _M_func(this);
+    };
+
+  public:
+    template <typename _Fn>
+    __func_task(_Fn&& __f) : _M_func{std::forward<_Fn>(__f)}
+    {
+    }
+
+    _Func&
+    body()
+    {
+        return _M_func;
+    }
+};
+
+template <typename _Func>
+class __root_task
+{
+    tbb::task* _M_task;
+
+  public:
+    template <typename... Args>
+    __root_task(Args&&... args)
+        : _M_task{new (tbb::task::allocate_root()) __func_task<_Func>{_Func(std::forward<Args>(args)...)}}
+    {
+    }
+
+    friend class __task;
+    friend class __func_task<_Func>;
+};
+
+#else  // TBB_INTERFACE_VERSION <= 12000
+class __task : public tbb::detail::d1::task
+{
+  protected:
+    tbb::detail::d1::small_object_allocator _M_allocator{};
+    tbb::detail::d1::execution_data* _M_execute_data{};
+    __task* _M_parent{};
+    std::atomic<int> _M_refcount{};
+    bool _M_recycle{};
+
+    template <typename _Fn>
+    __task*
+    allocate_func_task(_Fn&& __f)
+    {
+        _PSTL_ASSERT(_M_execute_data != nullptr);
+        tbb::detail::d1::small_object_allocator __alloc{};
+        auto __t =
+            __alloc.new_object<__func_task<typename std::decay<_Fn>::type>>(*_M_execute_data, std::forward<_Fn>(__f));
+        __t->_M_allocator = __alloc;
+        return __t;
+    }
+
+  public:
+    __task*
+    parent()
+    {
+        return _M_parent;
+    }
+
+    void
+    set_ref_count(int __n)
+    {
+        _M_refcount.store(__n, std::memory_order_release);
+    }
+
+    template <typename _Fn>
+    __task*
+    make_continuation(_Fn&& __f)
+    {
+        auto __t = allocate_func_task(std::forward<_Fn&&>(__f));
+        __t->_M_parent = _M_parent;
+        _M_parent = nullptr;
+        return __t;
+    }
+
+    template <typename _Fn>
+    __task*
+    make_child_of(__task* __parent, _Fn&& __f)
+    {
+        auto __t = allocate_func_task(std::forward<_Fn&&>(__f));
+        __t->_M_parent = __parent;
+        return __t;
+    }
+
+    template <typename _Fn>
+    __task*
+    make_additional_child_of(__task* __parent, _Fn&& __f)
+    {
+        auto __t = make_child_of(__parent, std::forward<_Fn>(__f));
+        _PSTL_ASSERT(__parent->_M_refcount.load(std::memory_order_relaxed) > 0);
+        ++__parent->_M_refcount;
+        return __t;
+    }
+
+    inline void
+    recycle_as_continuation()
+    {
+        _M_recycle = true;
+    }
+
+    inline void
+    recycle_as_child_of(__task* parent)
+    {
+        _M_recycle = true;
+        _M_parent = parent;
+    }
+
+    inline void
+    spawn(__task* __t)
+    {
+        _PSTL_ASSERT(_M_execute_data != nullptr);
+        tbb::detail::d1::spawn(*__t, *_M_execute_data->context);
+    }
+
+    template <typename _Fn>
+    static inline void
+    spawn_root_and_wait(__root_task<_Fn>& __root)
+    {
+        tbb::detail::d1::execute_and_wait(*__root._M_func_task, __root._M_context, __root._M_wait_object,
+                                          __root._M_context);
+    }
+
+    template <typename _Func>
+    friend class __func_task;
+};
+
+template <typename _Func>
+class __func_task : public __task
+{
+    _Func _M_func;
+
+    __task*
+    execute(tbb::detail::d1::execution_data& __ed) override
+    {
+        _M_execute_data = &__ed;
+        _M_recycle = false;
+        __task* __next = _M_func(this);
+        return finalize(__next);
+    };
+
+    __task*
+    cancel(tbb::detail::d1::execution_data& __ed) override
+    {
+        return finalize(nullptr);
+    }
+
+    __task*
+    finalize(__task* __next)
+    {
+        bool __recycle = _M_recycle;
+        _M_recycle = false;
+
+        if (__recycle)
+        {
+            return __next;
+        }
+
+        auto __parent = _M_parent;
+        auto __alloc = _M_allocator;
+        auto __ed = _M_execute_data;
+
+        this->~__func_task();
+
+        _PSTL_ASSERT(__parent != nullptr);
+        _PSTL_ASSERT(__parent->_M_refcount.load(std::memory_order_relaxed) > 0);
+        if (--__parent->_M_refcount == 0)
+        {
+            _PSTL_ASSERT(__next == nullptr);
+            __alloc.deallocate(this, *__ed);
+            return __parent;
+        }
+
+        return __next;
+    }
+
+    friend class __root_task<_Func>;
+
+  public:
+    template <typename _Fn>
+    __func_task(_Fn&& __f) : _M_func(std::forward<_Fn>(__f))
+    {
+    }
+
+    _Func&
+    body()
+    {
+        return _M_func;
+    }
+};
+
+template <typename _Func>
+class __root_task : public __task
+{
+    __task*
+    execute(tbb::detail::d1::execution_data& __ed) override
+    {
+        _M_wait_object.release();
+        return nullptr;
+    };
+
+    __task*
+    cancel(tbb::detail::d1::execution_data& __ed) override
+    {
+        _M_wait_object.release();
+        return nullptr;
+    }
+
+    __func_task<_Func>* _M_func_task{};
+    tbb::detail::d1::wait_context _M_wait_object{0};
+    tbb::task_group_context _M_context{};
+
+  public:
+    template <typename... Args>
+    __root_task(Args&&... args) : _M_wait_object{1}
+    {
+        tbb::detail::d1::small_object_allocator __alloc{};
+        _M_func_task = __alloc.new_object<__func_task<_Func>>(_Func(std::forward<Args>(args)...));
+        _M_func_task->_M_allocator = __alloc;
+        _M_func_task->_M_parent = this;
+        _M_refcount.store(1, std::memory_order_relaxed);
+    }
+
+    friend class __task;
+};
+#endif // TBB_INTERFACE_VERSION <= 12000
+
+template <typename _RandomAccessIterator1, typename _RandomAccessIterator2, typename _Compare, typename _Cleanup,
+          typename _LeafMerge>
+class __merge_func
+{
+    typedef typename std::iterator_traits<_RandomAccessIterator1>::difference_type _DifferenceType1;
+    typedef typename std::iterator_traits<_RandomAccessIterator2>::difference_type _DifferenceType2;
+    typedef typename std::common_type<_DifferenceType1, _DifferenceType2>::type _SizeType;
+    typedef typename std::iterator_traits<_RandomAccessIterator1>::value_type _ValueType;
+
+    _RandomAccessIterator1 _M_x_beg;
+    _RandomAccessIterator2 _M_z_beg;
+
+    _SizeType _M_xs, _M_xe;
+    _SizeType _M_ys, _M_ye;
+    _SizeType _M_zs;
+    _Compare _M_comp;
+    _LeafMerge _M_leaf_merge;
+    _SizeType _M_nsort; //number of elements to be sorted for partial_sort alforithm
+
+    static const _SizeType __merge_cut_off = _PSTL_MERGE_CUT_OFF;
+
+    bool _root;   //means a task is merging root task
+    bool _x_orig; //"true" means X(or left ) subrange is in the original container; false - in the buffer
+    bool _y_orig; //"true" means Y(or right) subrange is in the original container; false - in the buffer
+    bool _split; //"true" means a merge task is a split task for parallel merging, the execution logic differs
+
+    bool
+    is_partial() const
+    {
+        return _M_nsort > 0;
+    }
+
+    struct __move_value
+    {
+        template <typename Iterator1, typename Iterator2>
+        void
+        operator()(Iterator1 __x, Iterator2 __z)
+        {
+            *__z = std::move(*__x);
+        }
+    };
+
+    struct __move_value_construct
+    {
+        template <typename Iterator1, typename Iterator2>
+        void
+        operator()(Iterator1 __x, Iterator2 __z)
+        {
+            ::new (std::addressof(*__z)) _ValueType(std::move(*__x));
+        }
+    };
+
+    struct __move_range
+    {
+        template <typename Iterator1, typename Iterator2>
+        Iterator2
+        operator()(Iterator1 __first1, Iterator1 __last1, Iterator2 __first2)
+        {
+            if (__last1 - __first1 < __merge_cut_off)
+                return std::move(__first1, __last1, __first2);
+
+            auto __n = __last1 - __first1;
+            tbb::parallel_for(tbb::blocked_range<_SizeType>(0, __n, __merge_cut_off),
+                              [__first1, __first2](const tbb::blocked_range<_SizeType>& __range) {
+                                  std::move(__first1 + __range.begin(), __first1 + __range.end(),
+                                            __first2 + __range.begin());
+                              });
+            return __first2 + __n;
+        }
+    };
+
+    struct __move_range_construct
+    {
+        template <typename Iterator1, typename Iterator2>
+        Iterator2
+        operator()(Iterator1 __first1, Iterator1 __last1, Iterator2 __first2)
+        {
+            if (__last1 - __first1 < __merge_cut_off)
+            {
+                for (; __first1 != __last1; ++__first1, ++__first2)
+                    __move_value_construct()(__first1, __first2);
+                return __first2;
+            }
+
+            auto __n = __last1 - __first1;
+            tbb::parallel_for(tbb::blocked_range<_SizeType>(0, __n, __merge_cut_off),
+                              [__first1, __first2](const tbb::blocked_range<_SizeType>& __range) {
+                                  for (auto i = __range.begin(); i != __range.end(); ++i)
+                                      __move_value_construct()(__first1 + i, __first2 + i);
+                              });
+            return __first2 + __n;
+        }
+    };
+
+    struct __cleanup_range
+    {
+        template <typename Iterator>
+        void
+        operator()(Iterator __first, Iterator __last)
+        {
+            if (__last - __first < __merge_cut_off)
+                _Cleanup()(__first, __last);
+            else
+            {
+                auto __n = __last - __first;
+                tbb::parallel_for(tbb::blocked_range<_SizeType>(0, __n, __merge_cut_off),
+                                  [__first](const tbb::blocked_range<_SizeType>& __range) {
+                                      _Cleanup()(__first + __range.begin(), __first + __range.end());
+                                  });
+            }
+        }
+    };
+
+  public:
+    __merge_func(_SizeType __xs, _SizeType __xe, _SizeType __ys, _SizeType __ye, _SizeType __zs, _Compare __comp,
+                 _Cleanup, _LeafMerge __leaf_merge, _SizeType __nsort, _RandomAccessIterator1 __x_beg,
+                 _RandomAccessIterator2 __z_beg, bool __x_orig, bool __y_orig, bool __root)
+        : _M_xs(__xs), _M_xe(__xe), _M_ys(__ys), _M_ye(__ye), _M_zs(__zs), _M_x_beg(__x_beg), _M_z_beg(__z_beg),
+          _M_comp(__comp), _M_leaf_merge(__leaf_merge), _M_nsort(__nsort), _root(__root),
+          _x_orig(__x_orig), _y_orig(__y_orig), _split(false)
+    {
+    }
+
+    bool
+    is_left(_SizeType __idx) const
+    {
+        return _M_xs == __idx;
+    }
+
+    template <typename IndexType>
+    void
+    set_odd(IndexType __idx, bool __on_off)
+    {
+        if (is_left(__idx))
+            _x_orig = __on_off;
+        else
+            _y_orig = __on_off;
+    }
+
+    __task*
+    operator()(__task* __self);
+
+  private:
+    __merge_func*
+    parent_merge(__task* __self) const
+    {
+        return _root ? nullptr : &static_cast<__func_task<__merge_func>*>(__self->parent())->body();
+    }
+    bool
+    x_less_y()
+    {
+        const auto __nx = (_M_xe - _M_xs);
+        const auto __ny = (_M_ye - _M_ys);
+        _PSTL_ASSERT(__nx > 0 && __ny > 0);
+
+        _PSTL_ASSERT(_x_orig == _y_orig);
+        _PSTL_ASSERT(!is_partial());
+
+        if (_x_orig)
+        {
+            _PSTL_ASSERT(std::is_sorted(_M_x_beg + _M_xs, _M_x_beg + _M_xe, _M_comp));
+            _PSTL_ASSERT(std::is_sorted(_M_x_beg + _M_ys, _M_x_beg + _M_ye, _M_comp));
+            return !_M_comp(*(_M_x_beg + _M_ys), *(_M_x_beg + _M_xe - 1));
+        }
+
+        _PSTL_ASSERT(std::is_sorted(_M_z_beg + _M_xs, _M_z_beg + _M_xe, _M_comp));
+        _PSTL_ASSERT(std::is_sorted(_M_z_beg + _M_ys, _M_z_beg + _M_ye, _M_comp));
+        return !_M_comp(*(_M_z_beg + _M_zs + __nx), *(_M_z_beg + _M_zs + __nx - 1));
+    }
+    void
+    move_x_range()
+    {
+        const auto __nx = (_M_xe - _M_xs);
+        const auto __ny = (_M_ye - _M_ys);
+        _PSTL_ASSERT(__nx > 0 && __ny > 0);
+
+        if (_x_orig)
+            __move_range_construct()(_M_x_beg + _M_xs, _M_x_beg + _M_xe, _M_z_beg + _M_zs);
+        else
+        {
+            __move_range()(_M_z_beg + _M_zs, _M_z_beg + _M_zs + __nx, _M_x_beg + _M_xs);
+            __cleanup_range()(_M_z_beg + _M_zs, _M_z_beg + _M_zs + __nx);
+        }
+
+        _x_orig = !_x_orig;
+    }
+    void
+    move_y_range()
+    {
+        const auto __nx = (_M_xe - _M_xs);
+        const auto __ny = (_M_ye - _M_ys);
+
+        if (_y_orig)
+            __move_range_construct()(_M_x_beg + _M_ys, _M_x_beg + _M_ye, _M_z_beg + _M_zs + __nx);
+        else
+        {
+            __move_range()(_M_z_beg + _M_zs + __nx, _M_z_beg + _M_zs + __nx + __ny, _M_x_beg + _M_ys);
+            __cleanup_range()(_M_z_beg + _M_zs + __nx, _M_z_beg + _M_zs + __nx + __ny);
+        }
+
+        _y_orig = !_y_orig;
+    }
+    __task*
+    merge_ranges(__task* __self)
+    {
+        _PSTL_ASSERT(_x_orig == _y_orig); //two merged subrange must be lie into the same buffer
+
+        const auto __nx = (_M_xe - _M_xs);
+        const auto __ny = (_M_ye - _M_ys);
+        const auto __n = __nx + __ny;
+
+        // need to merge {x} and {y}
+        if (__n > __merge_cut_off)
+            return split_merging(__self);
+
+        //merge to buffer
+        if (_x_orig)
+        {
+            _M_leaf_merge(_M_x_beg + _M_xs, _M_x_beg + _M_xe, _M_x_beg + _M_ys, _M_x_beg + _M_ye, _M_z_beg + _M_zs,
+                          _M_comp, __move_value_construct(), __move_value_construct(), __move_range_construct(),
+                          __move_range_construct());
+            _PSTL_ASSERT(parent_merge(__self)); //not root merging task
+        }
+        //merge to "origin"
+        else
+        {
+            _PSTL_ASSERT(_x_orig == _y_orig);
+
+            _PSTL_ASSERT(is_partial() || std::is_sorted(_M_z_beg + _M_xs, _M_z_beg + _M_xe, _M_comp));
+            _PSTL_ASSERT(is_partial() || std::is_sorted(_M_z_beg + _M_ys, _M_z_beg + _M_ye, _M_comp));
+
+            const auto __nx = (_M_xe - _M_xs);
+            const auto __ny = (_M_ye - _M_ys);
+
+            _M_leaf_merge(_M_z_beg + _M_xs, _M_z_beg + _M_xe, _M_z_beg + _M_ys, _M_z_beg + _M_ye, _M_x_beg + _M_zs,
+                          _M_comp, __move_value(), __move_value(), __move_range(), __move_range());
+
+            __cleanup_range()(_M_z_beg + _M_xs, _M_z_beg + _M_xe);
+            __cleanup_range()(_M_z_beg + _M_ys, _M_z_beg + _M_ye);
+        }
+        return nullptr;
+    }
+
+    __task*
+    process_ranges(__task* __self)
+    {
+        _PSTL_ASSERT(_x_orig == _y_orig);
+        _PSTL_ASSERT(!_split);
+
+        auto p = parent_merge(__self);
+
+        if (!p)
+        { //root merging task
+
+            //optimization, just for sort algorithm, //{x} <= {y}
+            if (!is_partial() && x_less_y()) //we have a solution
+            {
+                if (!_x_orig)
+                {                   //we have to move the solution to the origin
+                    move_x_range(); //parallel moving
+                    move_y_range(); //parallel moving
+                }
+                return nullptr;
+            }
+            //else: if we have data in the origin,
+            //we have to move data to the buffer for final merging into the origin.
+            if (_x_orig)
+            {
+                move_x_range(); //parallel moving
+                move_y_range(); //parallel moving
+            }
+            // need to merge {x} and {y}.
+            return merge_ranges(__self);
+        }
+        //else: not root merging task (parent_merge() == NULL)
+        //optimization, just for sort algorithm, //{x} <= {y}
+        if (!is_partial() && x_less_y())
+        {
+            const auto id_range = _M_zs;
+            p->set_odd(id_range, _x_orig);
+            return nullptr;
+        }
+        //else: we have to revert "_x(y)_orig" flag of the parent merging task
+        const auto id_range = _M_zs;
+        p->set_odd(id_range, !_x_orig);
+
+        return merge_ranges(__self);
+    }
+
+    //splitting as merge task into 2 of the same level
+    __task*
+    split_merging(__task* __self)
+    {
+        _PSTL_ASSERT(_x_orig == _y_orig);
+        const auto __nx = (_M_xe - _M_xs);
+        const auto __ny = (_M_ye - _M_ys);
+
+        _SizeType __xm{};
+        _SizeType __ym{};
+        if (__nx < __ny)
+        {
+            __ym = _M_ys + __ny / 2;
+
+            if (_x_orig)
+                __xm = std::upper_bound(_M_x_beg + _M_xs, _M_x_beg + _M_xe, *(_M_x_beg + __ym), _M_comp) - _M_x_beg;
+            else
+                __xm = std::upper_bound(_M_z_beg + _M_xs, _M_z_beg + _M_xe, *(_M_z_beg + __ym), _M_comp) - _M_z_beg;
+        }
+        else
+        {
+            __xm = _M_xs + __nx / 2;
+
+            if (_y_orig)
+                __ym = std::lower_bound(_M_x_beg + _M_ys, _M_x_beg + _M_ye, *(_M_x_beg + __xm), _M_comp) - _M_x_beg;
+            else
+                __ym = std::lower_bound(_M_z_beg + _M_ys, _M_z_beg + _M_ye, *(_M_z_beg + __xm), _M_comp) - _M_z_beg;
+        }
+
+        auto __zm = _M_zs + ((__xm - _M_xs) + (__ym - _M_ys));
+        __merge_func __right_func(__xm, _M_xe, __ym, _M_ye, __zm, _M_comp, _Cleanup(), _M_leaf_merge, _M_nsort,
+                                  _M_x_beg, _M_z_beg, _x_orig, _y_orig, _root);
+        __right_func._split = true;
+        auto __merge_task = __self->make_additional_child_of(__self->parent(), std::move(__right_func));
+        __self->spawn(__merge_task);
+        __self->recycle_as_continuation();
+
+        _M_xe = __xm;
+        _M_ye = __ym;
+        _split = true;
+
+        return __self;
+    }
+};
+
+template <typename _RandomAccessIterator1, typename _RandomAccessIterator2, typename __M_Compare, typename _Cleanup,
+          typename _LeafMerge>
+__task*
+__merge_func<_RandomAccessIterator1, _RandomAccessIterator2, __M_Compare, _Cleanup, _LeafMerge>::
+operator()(__task* __self)
+{
+    //a. split merge task into 2 of the same level; the special logic,
+    //without processing(process_ranges) adjacent sub-ranges x and y
+    if (_split)
+        return merge_ranges(__self);
+
+    //b. General merging of adjacent sub-ranges x and y (with optimization in case of {x} <= {y} )
+
+    //1. x and y are in the even buffer
+    //2. x and y are in the odd buffer
+    if (_x_orig == _y_orig)
+        return process_ranges(__self);
+
+    //3. x is in even buffer, y is in the odd buffer
+    //4. x is in odd buffer, y is in the even buffer
+    if (!parent_merge(__self))
+    { //root merge task
+        if (_x_orig)
+            move_x_range();
+        else
+            move_y_range();
+    }
+    else
+    {
+        const _SizeType __nx = (_M_xe - _M_xs);
+        const _SizeType __ny = (_M_ye - _M_ys);
+        _PSTL_ASSERT(__nx > 0);
+        _PSTL_ASSERT(__nx > 0);
+
+        if (__nx < __ny)
+            move_x_range();
+        else
+            move_y_range();
+    }
+
+    return process_ranges(__self);
+}
+
+template <typename _RandomAccessIterator1, typename _RandomAccessIterator2, typename _Compare, typename _LeafSort>
+class __stable_sort_func
+{
+  public:
+    typedef typename std::iterator_traits<_RandomAccessIterator1>::difference_type _DifferenceType1;
+    typedef typename std::iterator_traits<_RandomAccessIterator2>::difference_type _DifferenceType2;
+    typedef typename std::common_type<_DifferenceType1, _DifferenceType2>::type _SizeType;
+
+  private:
+    _RandomAccessIterator1 _M_xs, _M_xe, _M_x_beg;
+    _RandomAccessIterator2 _M_zs, _M_z_beg;
+    _Compare _M_comp;
+    _LeafSort _M_leaf_sort;
+    bool _M_root;
+    _SizeType _M_nsort; //zero or number of elements to be sorted for partial_sort alforithm
+
+  public:
+    __stable_sort_func(_RandomAccessIterator1 __xs, _RandomAccessIterator1 __xe, _RandomAccessIterator2 __zs,
+                       bool __root, _Compare __comp, _LeafSort __leaf_sort, _SizeType __nsort,
+                       _RandomAccessIterator1 __x_beg, _RandomAccessIterator2 __z_beg)
+        : _M_xs(__xs), _M_xe(__xe), _M_x_beg(__x_beg), _M_zs(__zs), _M_z_beg(__z_beg), _M_comp(__comp),
+          _M_leaf_sort(__leaf_sort), _M_root(__root), _M_nsort(__nsort)
+    {
+    }
+
+    __task*
+    operator()(__task* __self);
+};
+
+#define _PSTL_STABLE_SORT_CUT_OFF 500
+
+template <typename _RandomAccessIterator1, typename _RandomAccessIterator2, typename _Compare, typename _LeafSort>
+__task*
+__stable_sort_func<_RandomAccessIterator1, _RandomAccessIterator2, _Compare, _LeafSort>::operator()(__task* __self)
+{
+    typedef __merge_func<_RandomAccessIterator1, _RandomAccessIterator2, _Compare, __utils::__serial_destroy,
+                         __utils::__serial_move_merge>
+        _MergeTaskType;
+
+    const _SizeType __n = _M_xe - _M_xs;
+    const _SizeType __nmerge = _M_nsort > 0 ? _M_nsort : __n;
+    const _SizeType __sort_cut_off = _PSTL_STABLE_SORT_CUT_OFF;
+    if (__n <= __sort_cut_off)
+    {
+        _M_leaf_sort(_M_xs, _M_xe, _M_comp);
+        _PSTL_ASSERT(!_M_root);
+        return nullptr;
+    }
+
+    const _RandomAccessIterator1 __xm = _M_xs + __n / 2;
+    const _RandomAccessIterator2 __zm = _M_zs + (__xm - _M_xs);
+    const _RandomAccessIterator2 __ze = _M_zs + __n;
+    _MergeTaskType __m(_MergeTaskType(_M_xs - _M_x_beg, __xm - _M_x_beg, __xm - _M_x_beg, _M_xe - _M_x_beg,
+                                      _M_zs - _M_z_beg, _M_comp, __utils::__serial_destroy(),
+                                      __utils::__serial_move_merge(__nmerge), _M_nsort, _M_x_beg, _M_z_beg,
+                                      /*x_orig*/ true, /*y_orig*/ true, /*root*/ _M_root));
+    auto __parent = __self->make_continuation(std::move(__m));
+    __parent->set_ref_count(2);
+    auto __right = __self->make_child_of(
+        __parent, __stable_sort_func(__xm, _M_xe, __zm, false, _M_comp, _M_leaf_sort, _M_nsort, _M_x_beg, _M_z_beg));
+    __self->spawn(__right);
+    __self->recycle_as_child_of(__parent);
+    _M_root = false;
+    _M_xe = __xm;
+
+    return __self;
+}
+
+template <class _ExecutionPolicy, typename _RandomAccessIterator, typename _Compare, typename _LeafSort>
+void
+__parallel_stable_sort(__pstl::__internal::__tbb_backend_tag, _ExecutionPolicy&&, _RandomAccessIterator __xs,
+                       _RandomAccessIterator __xe, _Compare __comp, _LeafSort __leaf_sort, std::size_t __nsort = 0)
+{
+    tbb::this_task_arena::isolate([=, &__nsort]() {
+        //sorting based on task tree and parallel merge
+        typedef typename std::iterator_traits<_RandomAccessIterator>::value_type _ValueType;
+        typedef typename std::iterator_traits<_RandomAccessIterator>::difference_type _DifferenceType;
+        const _DifferenceType __n = __xe - __xs;
+        if (__nsort == __n)
+            __nsort = 0; // 'partial_sort' becames 'sort'
+
+        const _DifferenceType __sort_cut_off = _PSTL_STABLE_SORT_CUT_OFF;
+        if (__n > __sort_cut_off)
+        {
+            __buffer<_ValueType> __buf(__n);
+            __root_task<__stable_sort_func<_RandomAccessIterator, _ValueType*, _Compare, _LeafSort>> __root{
+                __xs, __xe, __buf.get(), true, __comp, __leaf_sort, __nsort, __xs, __buf.get()};
+            __task::spawn_root_and_wait(__root);
+            return;
+        }
+        //serial sort
+        __leaf_sort(__xs, __xe, __comp);
+    });
+}
+
+//------------------------------------------------------------------------
+// parallel_merge
+//------------------------------------------------------------------------
+template <typename _RandomAccessIterator1, typename _RandomAccessIterator2, typename _RandomAccessIterator3,
+          typename _Compare, typename _LeafMerge>
+class __merge_func_static
+{
+    _RandomAccessIterator1 _M_xs, _M_xe;
+    _RandomAccessIterator2 _M_ys, _M_ye;
+    _RandomAccessIterator3 _M_zs;
+    _Compare _M_comp;
+    _LeafMerge _M_leaf_merge;
+
+  public:
+    __merge_func_static(_RandomAccessIterator1 __xs, _RandomAccessIterator1 __xe, _RandomAccessIterator2 __ys,
+                        _RandomAccessIterator2 __ye, _RandomAccessIterator3 __zs, _Compare __comp,
+                        _LeafMerge __leaf_merge)
+        : _M_xs(__xs), _M_xe(__xe), _M_ys(__ys), _M_ye(__ye), _M_zs(__zs), _M_comp(__comp), _M_leaf_merge(__leaf_merge)
+    {
+    }
+
+    __task*
+    operator()(__task* __self);
+};
+
+//TODO: consider usage of parallel_for with a custom blocked_range
+template <typename _RandomAccessIterator1, typename _RandomAccessIterator2, typename _RandomAccessIterator3,
+          typename __M_Compare, typename _LeafMerge>
+__task*
+__merge_func_static<_RandomAccessIterator1, _RandomAccessIterator2, _RandomAccessIterator3, __M_Compare, _LeafMerge>::
+operator()(__task* __self)
+{
+    typedef typename std::iterator_traits<_RandomAccessIterator1>::difference_type _DifferenceType1;
+    typedef typename std::iterator_traits<_RandomAccessIterator2>::difference_type _DifferenceType2;
+    typedef typename std::common_type<_DifferenceType1, _DifferenceType2>::type _SizeType;
+    const _SizeType __n = (_M_xe - _M_xs) + (_M_ye - _M_ys);
+    const _SizeType __merge_cut_off = _PSTL_MERGE_CUT_OFF;
+    if (__n <= __merge_cut_off)
+    {
+        _M_leaf_merge(_M_xs, _M_xe, _M_ys, _M_ye, _M_zs, _M_comp);
+        return nullptr;
+    }
+
+    _RandomAccessIterator1 __xm;
+    _RandomAccessIterator2 __ym;
+    if (_M_xe - _M_xs < _M_ye - _M_ys)
+    {
+        __ym = _M_ys + (_M_ye - _M_ys) / 2;
+        __xm = std::upper_bound(_M_xs, _M_xe, *__ym, _M_comp);
+    }
+    else
+    {
+        __xm = _M_xs + (_M_xe - _M_xs) / 2;
+        __ym = std::lower_bound(_M_ys, _M_ye, *__xm, _M_comp);
+    }
+    const _RandomAccessIterator3 __zm = _M_zs + ((__xm - _M_xs) + (__ym - _M_ys));
+    auto __right = __self->make_additional_child_of(
+        __self->parent(), __merge_func_static(__xm, _M_xe, __ym, _M_ye, __zm, _M_comp, _M_leaf_merge));
+    __self->spawn(__right);
+    __self->recycle_as_continuation();
+    _M_xe = __xm;
+    _M_ye = __ym;
+
+    return __self;
+}
+
+template <class _ExecutionPolicy, typename _RandomAccessIterator1, typename _RandomAccessIterator2,
+          typename _RandomAccessIterator3, typename _Compare, typename _LeafMerge>
+void
+__parallel_merge(__pstl::__internal::__tbb_backend_tag, _ExecutionPolicy&&, _RandomAccessIterator1 __xs,
+                 _RandomAccessIterator1 __xe, _RandomAccessIterator2 __ys, _RandomAccessIterator2 __ye,
+                 _RandomAccessIterator3 __zs, _Compare __comp, _LeafMerge __leaf_merge)
+{
+    typedef typename std::iterator_traits<_RandomAccessIterator1>::difference_type _DifferenceType1;
+    typedef typename std::iterator_traits<_RandomAccessIterator2>::difference_type _DifferenceType2;
+    typedef typename std::common_type<_DifferenceType1, _DifferenceType2>::type _SizeType;
+    const _SizeType __n = (__xe - __xs) + (__ye - __ys);
+    const _SizeType __merge_cut_off = _PSTL_MERGE_CUT_OFF;
+    if (__n <= __merge_cut_off)
+    {
+        // Fall back on serial merge
+        __leaf_merge(__xs, __xe, __ys, __ye, __zs, __comp);
+    }
+    else
+    {
+        tbb::this_task_arena::isolate([=]() {
+            typedef __merge_func_static<_RandomAccessIterator1, _RandomAccessIterator2, _RandomAccessIterator3,
+                                        _Compare, _LeafMerge>
+                _TaskType;
+            __root_task<_TaskType> __root{__xs, __xe, __ys, __ye, __zs, __comp, __leaf_merge};
+            __task::spawn_root_and_wait(__root);
+        });
+    }
+}
+
+//------------------------------------------------------------------------
+// parallel_invoke
+//------------------------------------------------------------------------
+template <class _ExecutionPolicy, typename _F1, typename _F2>
+void
+__parallel_invoke(__pstl::__internal::__tbb_backend_tag, _ExecutionPolicy&&, _F1&& __f1, _F2&& __f2)
+{
+    //TODO: a version of tbb::this_task_arena::isolate with variadic arguments pack should be added in the future
+    tbb::this_task_arena::isolate([&]() { tbb::parallel_invoke(std::forward<_F1>(__f1), std::forward<_F2>(__f2)); });
+}
+
+} // namespace __tbb_backend
+} // namespace __pstl
+
+_PSTL_HIDE_FROM_ABI_POP
+
+#endif /* _PSTL_PARALLEL_BACKEND_TBB_H */
diff --git a/pstl/include/pstl/internal/parallel_backend_utils.h b/pstl/include/pstl/internal/parallel_backend_utils.h
new file mode 100644
index 0000000..e176d7e
--- /dev/null
+++ b/pstl/include/pstl/internal/parallel_backend_utils.h
@@ -0,0 +1,263 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_PARALLEL_BACKEND_UTILS_H
+#define _PSTL_PARALLEL_BACKEND_UTILS_H
+
+#include <iterator>
+#include <utility>
+#include "utils.h"
+
+#include "pstl_config.h"
+
+_PSTL_HIDE_FROM_ABI_PUSH
+
+namespace __pstl
+{
+
+namespace __utils
+{
+
+//! Destroy sequence [xs,xe)
+struct __serial_destroy
+{
+    template <typename _RandomAccessIterator>
+    void
+    operator()(_RandomAccessIterator __zs, _RandomAccessIterator __ze)
+    {
+        typedef typename std::iterator_traits<_RandomAccessIterator>::value_type _ValueType;
+        while (__zs != __ze)
+        {
+            --__ze;
+            (*__ze).~_ValueType();
+        }
+    }
+};
+
+//! Merge sequences [__xs,__xe) and [__ys,__ye) to output sequence [__zs,(__xe-__xs)+(__ye-__ys)), using std::move
+struct __serial_move_merge
+{
+    const std::size_t _M_nmerge;
+
+    explicit __serial_move_merge(std::size_t __nmerge) : _M_nmerge(__nmerge) {}
+    template <class _RandomAccessIterator1, class _RandomAccessIterator2, class _RandomAccessIterator3, class _Compare,
+              class _MoveValueX, class _MoveValueY, class _MoveSequenceX, class _MoveSequenceY>
+    void
+    operator()(_RandomAccessIterator1 __xs, _RandomAccessIterator1 __xe, _RandomAccessIterator2 __ys,
+               _RandomAccessIterator2 __ye, _RandomAccessIterator3 __zs, _Compare __comp, _MoveValueX __move_value_x,
+               _MoveValueY __move_value_y, _MoveSequenceX __move_sequence_x, _MoveSequenceY __move_sequence_y)
+    {
+        constexpr bool __same_move_val = std::is_same<_MoveValueX, _MoveValueY>::value;
+        constexpr bool __same_move_seq = std::is_same<_MoveSequenceX, _MoveSequenceY>::value;
+
+        auto __n = _M_nmerge;
+        _PSTL_ASSERT(__n > 0);
+
+        auto __nx = __xe - __xs;
+        //auto __ny = __ye - __ys;
+        _RandomAccessIterator3 __zs_beg = __zs;
+
+        if (__xs != __xe)
+        {
+            if (__ys != __ye)
+            {
+                for (;;)
+                {
+                    if (__comp(*__ys, *__xs))
+                    {
+                        const auto __i = __zs - __zs_beg;
+                        if (__i < __nx)
+                            __move_value_x(__ys, __zs);
+                        else
+                            __move_value_y(__ys, __zs);
+                        ++__zs, --__n;
+                        if (++__ys == __ye)
+                        {
+                            break;
+                        }
+                        else if (__n == 0)
+                        {
+                            const auto __j = __zs - __zs_beg;
+                            if (__same_move_seq || __j < __nx)
+                                __zs = __move_sequence_x(__ys, __ye, __zs);
+                            else
+                                __zs = __move_sequence_y(__ys, __ye, __zs);
+                            break;
+                        }
+                    }
+                    else
+                    {
+                        const auto __i = __zs - __zs_beg;
+                        if (__same_move_val || __i < __nx)
+                            __move_value_x(__xs, __zs);
+                        else
+                            __move_value_y(__xs, __zs);
+                        ++__zs, --__n;
+                        if (++__xs == __xe)
+                        {
+                            const auto __j = __zs - __zs_beg;
+                            if (__same_move_seq || __j < __nx)
+                                __move_sequence_x(__ys, __ye, __zs);
+                            else
+                                __move_sequence_y(__ys, __ye, __zs);
+                            return;
+                        }
+                        else if (__n == 0)
+                        {
+                            const auto __j = __zs - __zs_beg;
+                            if (__same_move_seq || __j < __nx)
+                            {
+                                __zs = __move_sequence_x(__xs, __xe, __zs);
+                                __move_sequence_x(__ys, __ye, __zs);
+                            }
+                            else
+                            {
+                                __zs = __move_sequence_y(__xs, __xe, __zs);
+                                __move_sequence_y(__ys, __ye, __zs);
+                            }
+                            return;
+                        }
+                    }
+                }
+            }
+            __ys = __xs;
+            __ye = __xe;
+        }
+        const auto __i = __zs - __zs_beg;
+        if (__same_move_seq || __i < __nx)
+            __move_sequence_x(__ys, __ye, __zs);
+        else
+            __move_sequence_y(__ys, __ye, __zs);
+    }
+};
+
+template <typename _ForwardIterator1, typename _ForwardIterator2, typename _OutputIterator, typename _Compare,
+          typename _CopyConstructRange>
+_OutputIterator
+__set_union_construct(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+                      _ForwardIterator2 __last2, _OutputIterator __result, _Compare __comp,
+                      _CopyConstructRange __cc_range)
+{
+    using _Tp = typename std::iterator_traits<_OutputIterator>::value_type;
+
+    for (; __first1 != __last1; ++__result)
+    {
+        if (__first2 == __last2)
+            return __cc_range(__first1, __last1, __result);
+        if (__comp(*__first2, *__first1))
+        {
+            ::new (std::addressof(*__result)) _Tp(*__first2);
+            ++__first2;
+        }
+        else
+        {
+            ::new (std::addressof(*__result)) _Tp(*__first1);
+            if (!__comp(*__first1, *__first2))
+                ++__first2;
+            ++__first1;
+        }
+    }
+    return __cc_range(__first2, __last2, __result);
+}
+
+template <typename _ForwardIterator1, typename _ForwardIterator2, typename _OutputIterator, typename _Compare>
+_OutputIterator
+__set_intersection_construct(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+                             _ForwardIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+    using _Tp = typename std::iterator_traits<_OutputIterator>::value_type;
+
+    for (; __first1 != __last1 && __first2 != __last2;)
+    {
+        if (__comp(*__first1, *__first2))
+            ++__first1;
+        else
+        {
+            if (!__comp(*__first2, *__first1))
+            {
+                ::new (std::addressof(*__result)) _Tp(*__first1);
+                ++__result;
+                ++__first1;
+            }
+            ++__first2;
+        }
+    }
+    return __result;
+}
+
+template <typename _ForwardIterator1, typename _ForwardIterator2, typename _OutputIterator, typename _Compare,
+          typename _CopyConstructRange>
+_OutputIterator
+__set_difference_construct(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+                           _ForwardIterator2 __last2, _OutputIterator __result, _Compare __comp,
+                           _CopyConstructRange __cc_range)
+{
+    using _Tp = typename std::iterator_traits<_OutputIterator>::value_type;
+
+    for (; __first1 != __last1;)
+    {
+        if (__first2 == __last2)
+            return __cc_range(__first1, __last1, __result);
+
+        if (__comp(*__first1, *__first2))
+        {
+            ::new (std::addressof(*__result)) _Tp(*__first1);
+            ++__result;
+            ++__first1;
+        }
+        else
+        {
+            if (!__comp(*__first2, *__first1))
+                ++__first1;
+            ++__first2;
+        }
+    }
+    return __result;
+}
+template <typename _ForwardIterator1, typename _ForwardIterator2, typename _OutputIterator, typename _Compare,
+          typename _CopyConstructRange>
+_OutputIterator
+__set_symmetric_difference_construct(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+                                     _ForwardIterator2 __last2, _OutputIterator __result, _Compare __comp,
+                                     _CopyConstructRange __cc_range)
+{
+    using _Tp = typename std::iterator_traits<_OutputIterator>::value_type;
+
+    for (; __first1 != __last1;)
+    {
+        if (__first2 == __last2)
+            return __cc_range(__first1, __last1, __result);
+
+        if (__comp(*__first1, *__first2))
+        {
+            ::new (std::addressof(*__result)) _Tp(*__first1);
+            ++__result;
+            ++__first1;
+        }
+        else
+        {
+            if (__comp(*__first2, *__first1))
+            {
+                ::new (std::addressof(*__result)) _Tp(*__first2);
+                ++__result;
+            }
+            else
+                ++__first1;
+            ++__first2;
+        }
+    }
+    return __cc_range(__first2, __last2, __result);
+}
+
+} // namespace __utils
+} // namespace __pstl
+
+_PSTL_HIDE_FROM_ABI_POP
+
+#endif /* _PSTL_PARALLEL_BACKEND_UTILS_H */
diff --git a/pstl/include/pstl/internal/parallel_impl.h b/pstl/include/pstl/internal/parallel_impl.h
new file mode 100644
index 0000000..76b3f43
--- /dev/null
+++ b/pstl/include/pstl/internal/parallel_impl.h
@@ -0,0 +1,90 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_PARALLEL_IMPL_H
+#define _PSTL_PARALLEL_IMPL_H
+
+#include "pstl_config.h"
+
+#include <atomic>
+// This header defines the minimum set of parallel routines required to support Parallel STL,
+// implemented on top of Intel(R) Threading Building Blocks (Intel(R) TBB) library
+
+_PSTL_HIDE_FROM_ABI_PUSH
+
+namespace __pstl
+{
+namespace __internal
+{
+
+//------------------------------------------------------------------------
+// parallel_find
+//-----------------------------------------------------------------------
+/** Return extremum value returned by brick f[i,j) for subranges [i,j) of [first,last)
+Each f[i,j) must return a value in [i,j). */
+template <class _BackendTag, class _ExecutionPolicy, class _Index, class _Brick, class _Compare>
+_Index
+__parallel_find(_BackendTag __tag, _ExecutionPolicy&& __exec, _Index __first, _Index __last, _Brick __f,
+                _Compare __comp, bool __b_first)
+{
+    typedef typename std::iterator_traits<_Index>::difference_type _DifferenceType;
+    const _DifferenceType __n = __last - __first;
+    _DifferenceType __initial_dist = __b_first ? __n : -1;
+    std::atomic<_DifferenceType> __extremum(__initial_dist);
+    // TODO: find out what is better here: parallel_for or parallel_reduce
+    __par_backend::__parallel_for(__tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                  [__comp, __f, __first, &__extremum](_Index __i, _Index __j)
+                                  {
+                                      // See "Reducing Contention Through Priority Updates", PPoPP '13, for discussion of
+                                      // why using a shared variable scales fairly well in this situation.
+                                      if (__comp(__i - __first, __extremum))
+                                      {
+                                          _Index __res = __f(__i, __j);
+                                          // If not '__last' returned then we found what we want so put this to extremum
+                                          if (__res != __j)
+                                          {
+                                              const _DifferenceType __k = __res - __first;
+                                              for (_DifferenceType __old = __extremum; __comp(__k, __old);
+                                                   __old = __extremum)
+                                              {
+                                                  __extremum.compare_exchange_weak(__old, __k);
+                                              }
+                                          }
+                                      }
+                                  });
+    return __extremum != __initial_dist ? __first + __extremum : __last;
+}
+
+//------------------------------------------------------------------------
+// parallel_or
+//------------------------------------------------------------------------
+//! Return true if brick f[i,j) returns true for some subrange [i,j) of [first,last)
+template <class _BackendTag, class _ExecutionPolicy, class _Index, class _Brick>
+bool
+__parallel_or(_BackendTag __tag, _ExecutionPolicy&& __exec, _Index __first, _Index __last, _Brick __f)
+{
+    std::atomic<bool> __found(false);
+    __par_backend::__parallel_for(__tag, std::forward<_ExecutionPolicy>(__exec), __first, __last,
+                                  [__f, &__found](_Index __i, _Index __j)
+                                  {
+                                      if (!__found.load(std::memory_order_relaxed) && __f(__i, __j))
+                                      {
+                                          __found.store(true, std::memory_order_relaxed);
+                                          __par_backend::__cancel_execution();
+                                      }
+                                  });
+    return __found;
+}
+
+} // namespace __internal
+} // namespace __pstl
+
+_PSTL_HIDE_FROM_ABI_POP
+
+#endif /* _PSTL_PARALLEL_IMPL_H */
diff --git a/pstl/include/pstl/internal/pstl_config.h b/pstl/include/pstl/internal/pstl_config.h
new file mode 100644
index 0000000..8303226
--- /dev/null
+++ b/pstl/include/pstl/internal/pstl_config.h
@@ -0,0 +1,204 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_CONFIG_H
+#define _PSTL_CONFIG_H
+
+#include <__pstl_config_site>
+
+// The version is XYYZ, where X is major, YY is minor, and Z is patch (i.e. X.YY.Z)
+#define _PSTL_VERSION 17000
+#define _PSTL_VERSION_MAJOR (_PSTL_VERSION / 1000)
+#define _PSTL_VERSION_MINOR ((_PSTL_VERSION % 1000) / 10)
+#define _PSTL_VERSION_PATCH (_PSTL_VERSION % 10)
+
+#if !defined(_PSTL_PAR_BACKEND_SERIAL) && !defined(_PSTL_PAR_BACKEND_TBB) && !defined(_PSTL_PAR_BACKEND_OPENMP)
+#    error "A parallel backend must be specified"
+#endif
+
+// Check the user-defined macro for warnings
+#if defined(PSTL_USAGE_WARNINGS)
+#    define _PSTL_USAGE_WARNINGS
+#endif
+
+#if defined(_LIBCPP_VERSION)
+#    include <__assert>
+#    define _PSTL_ASSERT(pred) _LIBCPP_ASSERT(pred, "")
+#elif defined(__GLIBCXX__)
+#    define _PSTL_ASSERT(pred) __glibcxx_assert(pred)
+#else
+#    include <cassert>
+#    define _PSTL_ASSERT(pred) (assert((pred)))
+#endif
+
+// Portability "#pragma" definition
+#ifdef _MSC_VER
+#    define _PSTL_PRAGMA(x) __pragma(x)
+#else
+#    define _PSTL_PRAGMA(x) _Pragma(#    x)
+#endif
+
+#define _PSTL_STRING_AUX(x) #x
+#define _PSTL_STRING(x) _PSTL_STRING_AUX(x)
+#define _PSTL_STRING_CONCAT(x, y) x #y
+
+#ifdef _PSTL_HIDE_FROM_ABI_PER_TU
+#    define _PSTL_HIDE_FROM_ABI_PUSH                                                                                   \
+        _Pragma("clang attribute push(__attribute__((internal_linkage)), apply_to=any(function,record))")
+#    define _PSTL_HIDE_FROM_ABI_POP _Pragma("clang attribute pop")
+#else
+#    define _PSTL_HIDE_FROM_ABI_PUSH /* nothing */
+#    define _PSTL_HIDE_FROM_ABI_POP  /* nothing */
+#endif
+
+// note that when ICC or Clang is in use, _PSTL_GCC_VERSION might not fully match
+// the actual GCC version on the system.
+#define _PSTL_GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
+
+#if defined(__clang__)
+// according to clang documentation, version can be vendor specific
+#    define _PSTL_CLANG_VERSION (__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__)
+#endif
+
+// Enable SIMD for compilers that support OpenMP 4.0
+#if (defined(_OPENMP) && _OPENMP >= 201307) || \
+    (defined(__INTEL_COMPILER) && __INTEL_COMPILER >= 1600) || \
+    (!defined(__INTEL_COMPILER) && _PSTL_GCC_VERSION >= 40900) || \
+    defined(__clang__)
+#    define _PSTL_PRAGMA_SIMD _PSTL_PRAGMA(omp simd)
+#    define _PSTL_PRAGMA_DECLARE_SIMD _PSTL_PRAGMA(omp declare simd)
+#    define _PSTL_PRAGMA_SIMD_REDUCTION(PRM) _PSTL_PRAGMA(omp simd reduction(PRM))
+#elif !defined(_MSC_VER) //#pragma simd
+#    define _PSTL_PRAGMA_SIMD _PSTL_PRAGMA(simd)
+#    define _PSTL_PRAGMA_DECLARE_SIMD
+#    define _PSTL_PRAGMA_SIMD_REDUCTION(PRM) _PSTL_PRAGMA(simd reduction(PRM))
+#else //no simd
+#    define _PSTL_PRAGMA_SIMD
+#    define _PSTL_PRAGMA_DECLARE_SIMD
+#    define _PSTL_PRAGMA_SIMD_REDUCTION(PRM)
+#endif //Enable SIMD
+
+#if defined(__INTEL_COMPILER)
+#    define _PSTL_PRAGMA_FORCEINLINE _PSTL_PRAGMA(forceinline)
+#else
+#    define _PSTL_PRAGMA_FORCEINLINE
+#endif
+
+#if defined(__INTEL_COMPILER) && __INTEL_COMPILER >= 1900
+#    define _PSTL_PRAGMA_SIMD_SCAN(PRM) _PSTL_PRAGMA(omp simd reduction(inscan, PRM))
+#    define _PSTL_PRAGMA_SIMD_INCLUSIVE_SCAN(PRM) _PSTL_PRAGMA(omp scan inclusive(PRM))
+#    define _PSTL_PRAGMA_SIMD_EXCLUSIVE_SCAN(PRM) _PSTL_PRAGMA(omp scan exclusive(PRM))
+#else
+#    define _PSTL_PRAGMA_SIMD_SCAN(PRM)
+#    define _PSTL_PRAGMA_SIMD_INCLUSIVE_SCAN(PRM)
+#    define _PSTL_PRAGMA_SIMD_EXCLUSIVE_SCAN(PRM)
+#endif
+
+// Should be defined to 1 for environments with a vendor implementation of C++17 execution policies
+#define _PSTL_CPP17_EXECUTION_POLICIES_PRESENT (_MSC_VER >= 1912 && _MSVC_LANG >= 201703L) ||                          \
+    (_GLIBCXX_RELEASE >= 9 && __GLIBCXX__ >= 20190503 && __cplusplus >= 201703L)
+
+#if (defined(_MSC_VER) && _MSC_VER >= 1900) || \
+    __cplusplus >= 201300L || \
+    __cpp_lib_robust_nonmodifying_seq_ops == 201304
+#   define _PSTL_CPP14_2RANGE_MISMATCH_EQUAL_PRESENT
+#endif
+#if (defined(_MSC_VER) && _MSC_VER >= 1900) || \
+    __cplusplus >= 201402L || \
+    __cpp_lib_make_reverse_iterator == 201402
+#   define _PSTL_CPP14_MAKE_REVERSE_ITERATOR_PRESENT
+#endif
+#if (defined(_MSC_VER) && _MSC_VER >= 1900) || __cplusplus >= 201402L
+#   define _PSTL_CPP14_INTEGER_SEQUENCE_PRESENT
+#endif
+#if (defined(__INTEL_COMPILER) && __INTEL_COMPILER >= 1700) || \
+    (defined(_MSC_FULL_VER) && _MSC_FULL_VER >= 190023918) || \
+    __cplusplus >= 201402L
+#   define _PSTL_CPP14_VARIABLE_TEMPLATES_PRESENT
+#endif
+
+#if defined(__INTEL_COMPILER) && __INTEL_COMPILER >= 1800
+#   define _PSTL_EARLYEXIT_PRESENT
+#   define _PSTL_MONOTONIC_PRESENT
+#endif
+
+#if (defined(__INTEL_COMPILER) && __INTEL_COMPILER >= 1900) || \
+    (!defined(__INTEL_COMPILER) && _PSTL_GCC_VERSION >= 40900) || \
+    (defined(_OPENMP) && _OPENMP >= 201307)
+#    define _PSTL_UDR_PRESENT
+#endif
+
+#if defined(__INTEL_COMPILER) && __INTEL_COMPILER >= 1900 && __INTEL_COMPILER_BUILD_DATE >= 20180626
+#   define _PSTL_UDS_PRESENT
+#endif
+
+#if defined(_PSTL_EARLYEXIT_PRESENT)
+#    define _PSTL_PRAGMA_SIMD_EARLYEXIT _PSTL_PRAGMA(omp simd early_exit)
+#else
+#    define _PSTL_PRAGMA_SIMD_EARLYEXIT
+#endif
+
+#if defined(_PSTL_MONOTONIC_PRESENT)
+#    define _PSTL_PRAGMA_SIMD_ORDERED_MONOTONIC(PRM) _PSTL_PRAGMA(omp ordered simd monotonic(PRM))
+#    define _PSTL_PRAGMA_SIMD_ORDERED_MONOTONIC_2ARGS(PRM1, PRM2) _PSTL_PRAGMA(omp ordered simd monotonic(PRM1, PRM2))
+#else
+#    define _PSTL_PRAGMA_SIMD_ORDERED_MONOTONIC(PRM)
+#    define _PSTL_PRAGMA_SIMD_ORDERED_MONOTONIC_2ARGS(PRM1, PRM2)
+#endif
+
+// Declaration of reduction functor, where
+// NAME - the name of the functor
+// OP - type of the callable object with the reduction operation
+// omp_in - refers to the local partial result
+// omp_out - refers to the final value of the combiner operator
+// omp_priv - refers to the private copy of the initial value
+// omp_orig - refers to the original variable to be reduced
+#define _PSTL_PRAGMA_DECLARE_REDUCTION(NAME, OP)                                                                       \
+    _PSTL_PRAGMA(omp declare reduction(NAME:OP : omp_out(omp_in)) initializer(omp_priv = omp_orig))
+
+#if defined(__INTEL_COMPILER) && __INTEL_COMPILER >= 1600
+#    define _PSTL_PRAGMA_VECTOR_UNALIGNED _PSTL_PRAGMA(vector unaligned)
+#else
+#    define _PSTL_PRAGMA_VECTOR_UNALIGNED
+#endif
+
+// Check the user-defined macro to use non-temporal stores
+#if defined(PSTL_USE_NONTEMPORAL_STORES) && (__INTEL_COMPILER >= 1600)
+#    define _PSTL_USE_NONTEMPORAL_STORES_IF_ALLOWED _PSTL_PRAGMA(vector nontemporal)
+#else
+#    define _PSTL_USE_NONTEMPORAL_STORES_IF_ALLOWED
+#endif
+
+#if defined(_MSC_VER) || defined(__INTEL_COMPILER) // the preprocessors don't type a message location
+#    define _PSTL_PRAGMA_LOCATION __FILE__ ":" _PSTL_STRING(__LINE__) ": [Parallel STL message]: "
+#else
+#    define _PSTL_PRAGMA_LOCATION " [Parallel STL message]: "
+#endif
+
+#define _PSTL_PRAGMA_MESSAGE_IMPL(x) _PSTL_PRAGMA(message(_PSTL_STRING_CONCAT(_PSTL_PRAGMA_LOCATION, x)))
+
+#if defined(_PSTL_USAGE_WARNINGS)
+#    define _PSTL_PRAGMA_MESSAGE(x) _PSTL_PRAGMA_MESSAGE_IMPL(x)
+#    define _PSTL_PRAGMA_MESSAGE_POLICIES(x) _PSTL_PRAGMA_MESSAGE_IMPL(x)
+#else
+#    define _PSTL_PRAGMA_MESSAGE(x)
+#    define _PSTL_PRAGMA_MESSAGE_POLICIES(x)
+#endif
+
+// broken macros
+#if (defined(__GLIBCXX__) && __GLIBCXX__ < 20150716) || \
+    (defined(_MSC_VER) && _MSC_VER < 1800)
+#   define _PSTL_CPP11_STD_ROTATE_BROKEN
+#endif
+
+#if defined(__INTEL_COMPILER) && __INTEL_COMPILER == 1800
+#   define _PSTL_ICC_18_OMP_SIMD_BROKEN
+#endif
+
+#endif /* _PSTL_CONFIG_H */
diff --git a/pstl/include/pstl/internal/unseq_backend_simd.h b/pstl/include/pstl/internal/unseq_backend_simd.h
new file mode 100644
index 0000000..9521a42
--- /dev/null
+++ b/pstl/include/pstl/internal/unseq_backend_simd.h
@@ -0,0 +1,862 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_UNSEQ_BACKEND_SIMD_H
+#define _PSTL_UNSEQ_BACKEND_SIMD_H
+
+#include <type_traits>
+
+#include "pstl_config.h"
+#include "utils.h"
+
+// This header defines the minimum set of vector routines required
+// to support parallel STL.
+
+_PSTL_HIDE_FROM_ABI_PUSH
+
+namespace __pstl
+{
+namespace __unseq_backend
+{
+
+// Expect vector width up to 64 (or 512 bit)
+const std::size_t __lane_size = 64;
+
+template <class _Iterator, class _DifferenceType, class _Function>
+_Iterator
+__simd_walk_1(_Iterator __first, _DifferenceType __n, _Function __f) noexcept
+{
+    _PSTL_PRAGMA_SIMD
+    for (_DifferenceType __i = 0; __i < __n; ++__i)
+        __f(__first[__i]);
+
+    return __first + __n;
+}
+
+template <class _Iterator1, class _DifferenceType, class _Iterator2, class _Function>
+_Iterator2
+__simd_walk_2(_Iterator1 __first1, _DifferenceType __n, _Iterator2 __first2, _Function __f) noexcept
+{
+    _PSTL_PRAGMA_SIMD
+    for (_DifferenceType __i = 0; __i < __n; ++__i)
+        __f(__first1[__i], __first2[__i]);
+    return __first2 + __n;
+}
+
+template <class _Iterator1, class _DifferenceType, class _Iterator2, class _Iterator3, class _Function>
+_Iterator3
+__simd_walk_3(_Iterator1 __first1, _DifferenceType __n, _Iterator2 __first2, _Iterator3 __first3,
+              _Function __f) noexcept
+{
+    _PSTL_PRAGMA_SIMD
+    for (_DifferenceType __i = 0; __i < __n; ++__i)
+        __f(__first1[__i], __first2[__i], __first3[__i]);
+    return __first3 + __n;
+}
+
+// TODO: check whether __simd_first() can be used here
+template <class _Index, class _DifferenceType, class _Pred>
+bool
+__simd_or(_Index __first, _DifferenceType __n, _Pred __pred) noexcept
+{
+#if defined(_PSTL_EARLYEXIT_PRESENT)
+    _DifferenceType __i;
+    _PSTL_PRAGMA_VECTOR_UNALIGNED
+    _PSTL_PRAGMA_SIMD_EARLYEXIT
+    for (__i = 0; __i < __n; ++__i)
+        if (__pred(__first[__i]))
+            break;
+    return __i < __n;
+#else
+    _DifferenceType __block_size = 4 < __n ? 4 : __n;
+    const _Index __last = __first + __n;
+    while (__last != __first)
+    {
+        int32_t __flag = 1;
+        _PSTL_PRAGMA_SIMD_REDUCTION(& : __flag)
+        for (_DifferenceType __i = 0; __i < __block_size; ++__i)
+            if (__pred(*(__first + __i)))
+                __flag = 0;
+        if (!__flag)
+            return true;
+
+        __first += __block_size;
+        if (__last - __first >= __block_size << 1)
+        {
+            // Double the block _Size.  Any unnecessary iterations can be amortized against work done so far.
+            __block_size <<= 1;
+        }
+        else
+        {
+            __block_size = __last - __first;
+        }
+    }
+    return false;
+#endif
+}
+
+template <class _Index, class _DifferenceType, class _Compare>
+_Index
+__simd_first(_Index __first, _DifferenceType __begin, _DifferenceType __end, _Compare __comp) noexcept
+{
+#if defined(_PSTL_EARLYEXIT_PRESENT)
+    _DifferenceType __i = __begin;
+    _PSTL_PRAGMA_VECTOR_UNALIGNED // Do not generate peel loop part
+        _PSTL_PRAGMA_SIMD_EARLYEXIT for (; __i < __end; ++__i)
+    {
+        if (__comp(__first, __i))
+        {
+            break;
+        }
+    }
+    return __first + __i;
+#else
+    // Experiments show good block sizes like this
+    const _DifferenceType __block_size = 8;
+    alignas(__lane_size) _DifferenceType __lane[__block_size] = {0};
+    while (__end - __begin >= __block_size)
+    {
+        _DifferenceType __found = 0;
+        _PSTL_PRAGMA_VECTOR_UNALIGNED // Do not generate peel loop part
+            _PSTL_PRAGMA_SIMD_REDUCTION(|
+                                        : __found) for (_DifferenceType __i = __begin; __i < __begin + __block_size;
+                                                        ++__i)
+        {
+            const _DifferenceType __t = __comp(__first, __i);
+            __lane[__i - __begin] = __t;
+            __found |= __t;
+        }
+        if (__found)
+        {
+            _DifferenceType __i;
+            // This will vectorize
+            for (__i = 0; __i < __block_size; ++__i)
+            {
+                if (__lane[__i])
+                {
+                    break;
+                }
+            }
+            return __first + __begin + __i;
+        }
+        __begin += __block_size;
+    }
+
+    //Keep remainder scalar
+    while (__begin != __end)
+    {
+        if (__comp(__first, __begin))
+        {
+            return __first + __begin;
+        }
+        ++__begin;
+    }
+    return __first + __end;
+#endif //_PSTL_EARLYEXIT_PRESENT
+}
+
+template <class _Index1, class _DifferenceType, class _Index2, class _Pred>
+std::pair<_Index1, _Index2>
+__simd_first(_Index1 __first1, _DifferenceType __n, _Index2 __first2, _Pred __pred) noexcept
+{
+#if defined(_PSTL_EARLYEXIT_PRESENT)
+    _DifferenceType __i = 0;
+    _PSTL_PRAGMA_VECTOR_UNALIGNED
+    _PSTL_PRAGMA_SIMD_EARLYEXIT
+    for (; __i < __n; ++__i)
+        if (__pred(__first1[__i], __first2[__i]))
+            break;
+    return std::make_pair(__first1 + __i, __first2 + __i);
+#else
+    const _Index1 __last1 = __first1 + __n;
+    const _Index2 __last2 = __first2 + __n;
+    // Experiments show good block sizes like this
+    const _DifferenceType __block_size = 8;
+    alignas(__lane_size) _DifferenceType __lane[__block_size] = {0};
+    while (__last1 - __first1 >= __block_size)
+    {
+        _DifferenceType __found = 0;
+        _DifferenceType __i;
+        _PSTL_PRAGMA_VECTOR_UNALIGNED // Do not generate peel loop part
+            _PSTL_PRAGMA_SIMD_REDUCTION(|
+                                        : __found) for (__i = 0; __i < __block_size; ++__i)
+        {
+            const _DifferenceType __t = __pred(__first1[__i], __first2[__i]);
+            __lane[__i] = __t;
+            __found |= __t;
+        }
+        if (__found)
+        {
+            _DifferenceType __i2;
+            // This will vectorize
+            for (__i2 = 0; __i2 < __block_size; ++__i2)
+            {
+                if (__lane[__i2])
+                    break;
+            }
+            return std::make_pair(__first1 + __i2, __first2 + __i2);
+        }
+        __first1 += __block_size;
+        __first2 += __block_size;
+    }
+
+    //Keep remainder scalar
+    for (; __last1 != __first1; ++__first1, ++__first2)
+        if (__pred(*(__first1), *(__first2)))
+            return std::make_pair(__first1, __first2);
+
+    return std::make_pair(__last1, __last2);
+#endif //_PSTL_EARLYEXIT_PRESENT
+}
+
+template <class _Index, class _DifferenceType, class _Pred>
+_DifferenceType
+__simd_count(_Index __index, _DifferenceType __n, _Pred __pred) noexcept
+{
+    _DifferenceType __count = 0;
+    _PSTL_PRAGMA_SIMD_REDUCTION(+ : __count)
+    for (_DifferenceType __i = 0; __i < __n; ++__i)
+        if (__pred(*(__index + __i)))
+            ++__count;
+
+    return __count;
+}
+
+template <class _InputIterator, class _DifferenceType, class _OutputIterator, class _BinaryPredicate>
+_OutputIterator
+__simd_unique_copy(_InputIterator __first, _DifferenceType __n, _OutputIterator __result,
+                   _BinaryPredicate __pred) noexcept
+{
+    if (__n == 0)
+        return __result;
+
+    _DifferenceType __cnt = 1;
+    __result[0] = __first[0];
+
+    _PSTL_PRAGMA_SIMD
+    for (_DifferenceType __i = 1; __i < __n; ++__i)
+    {
+        _PSTL_PRAGMA_SIMD_ORDERED_MONOTONIC(__cnt : 1)
+        if (!__pred(__first[__i], __first[__i - 1]))
+        {
+            __result[__cnt] = __first[__i];
+            ++__cnt;
+        }
+    }
+    return __result + __cnt;
+}
+
+template <class _InputIterator, class _DifferenceType, class _OutputIterator, class _Assigner>
+_OutputIterator
+__simd_assign(_InputIterator __first, _DifferenceType __n, _OutputIterator __result, _Assigner __assigner) noexcept
+{
+    _PSTL_USE_NONTEMPORAL_STORES_IF_ALLOWED
+    _PSTL_PRAGMA_SIMD
+    for (_DifferenceType __i = 0; __i < __n; ++__i)
+        __assigner(__first + __i, __result + __i);
+    return __result + __n;
+}
+
+template <class _InputIterator, class _DifferenceType, class _OutputIterator, class _UnaryPredicate>
+_OutputIterator
+__simd_copy_if(_InputIterator __first, _DifferenceType __n, _OutputIterator __result, _UnaryPredicate __pred) noexcept
+{
+    _DifferenceType __cnt = 0;
+
+    _PSTL_PRAGMA_SIMD
+    for (_DifferenceType __i = 0; __i < __n; ++__i)
+    {
+        _PSTL_PRAGMA_SIMD_ORDERED_MONOTONIC(__cnt : 1)
+        if (__pred(__first[__i]))
+        {
+            __result[__cnt] = __first[__i];
+            ++__cnt;
+        }
+    }
+    return __result + __cnt;
+}
+
+template <class _InputIterator, class _DifferenceType, class _BinaryPredicate>
+_DifferenceType
+__simd_calc_mask_2(_InputIterator __first, _DifferenceType __n, bool* __mask, _BinaryPredicate __pred) noexcept
+{
+    _DifferenceType __count = 0;
+
+    _PSTL_PRAGMA_SIMD_REDUCTION(+ : __count)
+    for (_DifferenceType __i = 0; __i < __n; ++__i)
+    {
+        __mask[__i] = !__pred(__first[__i], __first[__i - 1]);
+        __count += __mask[__i];
+    }
+    return __count;
+}
+
+template <class _InputIterator, class _DifferenceType, class _UnaryPredicate>
+_DifferenceType
+__simd_calc_mask_1(_InputIterator __first, _DifferenceType __n, bool* __mask, _UnaryPredicate __pred) noexcept
+{
+    _DifferenceType __count = 0;
+
+    _PSTL_PRAGMA_SIMD_REDUCTION(+ : __count)
+    for (_DifferenceType __i = 0; __i < __n; ++__i)
+    {
+        __mask[__i] = __pred(__first[__i]);
+        __count += __mask[__i];
+    }
+    return __count;
+}
+
+template <class _InputIterator, class _DifferenceType, class _OutputIterator, class _Assigner>
+void
+__simd_copy_by_mask(_InputIterator __first, _DifferenceType __n, _OutputIterator __result, bool* __mask,
+                    _Assigner __assigner) noexcept
+{
+    _DifferenceType __cnt = 0;
+    _PSTL_PRAGMA_SIMD
+    for (_DifferenceType __i = 0; __i < __n; ++__i)
+    {
+        if (__mask[__i])
+        {
+            _PSTL_PRAGMA_SIMD_ORDERED_MONOTONIC(__cnt : 1)
+            {
+                __assigner(__first + __i, __result + __cnt);
+                ++__cnt;
+            }
+        }
+    }
+}
+
+template <class _InputIterator, class _DifferenceType, class _OutputIterator1, class _OutputIterator2>
+void
+__simd_partition_by_mask(_InputIterator __first, _DifferenceType __n, _OutputIterator1 __out_true,
+                         _OutputIterator2 __out_false, bool* __mask) noexcept
+{
+    _DifferenceType __cnt_true = 0, __cnt_false = 0;
+    _PSTL_PRAGMA_SIMD
+    for (_DifferenceType __i = 0; __i < __n; ++__i)
+    {
+        _PSTL_PRAGMA_SIMD_ORDERED_MONOTONIC_2ARGS(__cnt_true : 1, __cnt_false : 1)
+        if (__mask[__i])
+        {
+            __out_true[__cnt_true] = __first[__i];
+            ++__cnt_true;
+        }
+        else
+        {
+            __out_false[__cnt_false] = __first[__i];
+            ++__cnt_false;
+        }
+    }
+}
+
+template <class _Index, class _DifferenceType, class _Tp>
+_Index
+__simd_fill_n(_Index __first, _DifferenceType __n, const _Tp& __value) noexcept
+{
+    _PSTL_USE_NONTEMPORAL_STORES_IF_ALLOWED
+    _PSTL_PRAGMA_SIMD
+    for (_DifferenceType __i = 0; __i < __n; ++__i)
+        __first[__i] = __value;
+    return __first + __n;
+}
+
+template <class _Index, class _DifferenceType, class _Generator>
+_Index
+__simd_generate_n(_Index __first, _DifferenceType __size, _Generator __g) noexcept
+{
+    _PSTL_USE_NONTEMPORAL_STORES_IF_ALLOWED
+    _PSTL_PRAGMA_SIMD
+    for (_DifferenceType __i = 0; __i < __size; ++__i)
+        __first[__i] = __g();
+    return __first + __size;
+}
+
+template <class _Index, class _BinaryPredicate>
+_Index
+__simd_adjacent_find(_Index __first, _Index __last, _BinaryPredicate __pred, bool __or_semantic) noexcept
+{
+    if (__last - __first < 2)
+        return __last;
+
+    typedef typename std::iterator_traits<_Index>::difference_type _DifferenceType;
+    _DifferenceType __i = 0;
+
+#if defined(_PSTL_EARLYEXIT_PRESENT)
+    //Some compiler versions fail to compile the following loop when iterators are used. Indices are used instead
+    const _DifferenceType __n = __last - __first - 1;
+    _PSTL_PRAGMA_VECTOR_UNALIGNED
+    _PSTL_PRAGMA_SIMD_EARLYEXIT
+    for (; __i < __n; ++__i)
+        if (__pred(__first[__i], __first[__i + 1]))
+            break;
+
+    return __i < __n ? __first + __i : __last;
+#else
+    // Experiments show good block sizes like this
+    //TODO: to consider tuning block_size for various data types
+    const _DifferenceType __block_size = 8;
+    alignas(__lane_size) _DifferenceType __lane[__block_size] = {0};
+    while (__last - __first >= __block_size)
+    {
+        _DifferenceType __found = 0;
+        _PSTL_PRAGMA_VECTOR_UNALIGNED // Do not generate peel loop part
+            _PSTL_PRAGMA_SIMD_REDUCTION(|
+                                        : __found) for (__i = 0; __i < __block_size - 1; ++__i)
+        {
+            //TODO: to improve SIMD vectorization
+            const _DifferenceType __t = __pred(*(__first + __i), *(__first + __i + 1));
+            __lane[__i] = __t;
+            __found |= __t;
+        }
+
+        //Process a pair of elements on a boundary of a data block
+        if (__first + __block_size < __last && __pred(*(__first + __i), *(__first + __i + 1)))
+            __lane[__i] = __found = 1;
+
+        if (__found)
+        {
+            if (__or_semantic)
+                return __first;
+
+            // This will vectorize
+            for (__i = 0; __i < __block_size; ++__i)
+                if (__lane[__i])
+                    break;
+            return __first + __i; //As far as found is true a __result (__lane[__i] is true) is guaranteed
+        }
+        __first += __block_size;
+    }
+    //Process the rest elements
+    for (; __last - __first > 1; ++__first)
+        if (__pred(*__first, *(__first + 1)))
+            return __first;
+
+    return __last;
+#endif
+}
+
+// It was created to reduce the code inside std::enable_if
+template <typename _Tp, typename _BinaryOperation>
+using is_arithmetic_plus = std::integral_constant<bool, std::is_arithmetic<_Tp>::value &&
+                                                            std::is_same<_BinaryOperation, std::plus<_Tp>>::value>;
+
+template <typename _DifferenceType, typename _Tp, typename _BinaryOperation, typename _UnaryOperation>
+typename std::enable_if<is_arithmetic_plus<_Tp, _BinaryOperation>::value, _Tp>::type
+__simd_transform_reduce(_DifferenceType __n, _Tp __init, _BinaryOperation, _UnaryOperation __f) noexcept
+{
+    _PSTL_PRAGMA_SIMD_REDUCTION(+ : __init)
+    for (_DifferenceType __i = 0; __i < __n; ++__i)
+        __init += __f(__i);
+    return __init;
+}
+
+template <typename _Size, typename _Tp, typename _BinaryOperation, typename _UnaryOperation>
+typename std::enable_if<!is_arithmetic_plus<_Tp, _BinaryOperation>::value, _Tp>::type
+__simd_transform_reduce(_Size __n, _Tp __init, _BinaryOperation __binary_op, _UnaryOperation __f) noexcept
+{
+    const _Size __block_size = __lane_size / sizeof(_Tp);
+    if (__n > 2 * __block_size && __block_size > 1)
+    {
+        alignas(__lane_size) char __lane_[__lane_size];
+        _Tp* __lane = reinterpret_cast<_Tp*>(__lane_);
+
+        // initializer
+        _PSTL_PRAGMA_SIMD
+        for (_Size __i = 0; __i < __block_size; ++__i)
+        {
+            ::new (__lane + __i) _Tp(__binary_op(__f(__i), __f(__block_size + __i)));
+        }
+        // main loop
+        _Size __i = 2 * __block_size;
+        const _Size last_iteration = __block_size * (__n / __block_size);
+        for (; __i < last_iteration; __i += __block_size)
+        {
+            _PSTL_PRAGMA_SIMD
+            for (_Size __j = 0; __j < __block_size; ++__j)
+            {
+                __lane[__j] = __binary_op(__lane[__j], __f(__i + __j));
+            }
+        }
+        // remainder
+        _PSTL_PRAGMA_SIMD
+        for (_Size __j = 0; __j < __n - last_iteration; ++__j)
+        {
+            __lane[__j] = __binary_op(__lane[__j], __f(last_iteration + __j));
+        }
+        // combiner
+        for (_Size __j = 0; __j < __block_size; ++__j)
+        {
+            __init = __binary_op(__init, __lane[__j]);
+        }
+        // destroyer
+        _PSTL_PRAGMA_SIMD
+        for (_Size __j = 0; __j < __block_size; ++__j)
+        {
+            __lane[__j].~_Tp();
+        }
+    }
+    else
+    {
+        for (_Size __i = 0; __i < __n; ++__i)
+        {
+            __init = __binary_op(__init, __f(__i));
+        }
+    }
+    return __init;
+}
+
+// Exclusive scan for "+" and arithmetic types
+template <class _InputIterator, class _Size, class _OutputIterator, class _UnaryOperation, class _Tp,
+          class _BinaryOperation>
+typename std::enable_if<is_arithmetic_plus<_Tp, _BinaryOperation>::value, std::pair<_OutputIterator, _Tp>>::type
+__simd_scan(_InputIterator __first, _Size __n, _OutputIterator __result, _UnaryOperation __unary_op, _Tp __init,
+            _BinaryOperation, /*Inclusive*/ std::false_type)
+{
+    _PSTL_PRAGMA_SIMD_SCAN(+ : __init)
+    for (_Size __i = 0; __i < __n; ++__i)
+    {
+        __result[__i] = __init;
+        _PSTL_PRAGMA_SIMD_EXCLUSIVE_SCAN(__init)
+        __init += __unary_op(__first[__i]);
+    }
+    return std::make_pair(__result + __n, __init);
+}
+
+// As soon as we cannot call __binary_op in "combiner" we create a wrapper over _Tp to encapsulate __binary_op
+template <typename _Tp, typename _BinaryOp>
+struct _Combiner
+{
+    _Tp __value_;
+    _BinaryOp* __bin_op; // Here is a pointer to function because of default ctor
+
+    _Combiner() : __value_{}, __bin_op(nullptr) {}
+    _Combiner(const _Tp& value, const _BinaryOp* bin_op) : __value_(value), __bin_op(const_cast<_BinaryOp*>(bin_op)) {}
+    _Combiner(const _Combiner& __obj) : __value_{}, __bin_op(__obj.__bin_op) {}
+
+    void
+    operator()(const _Combiner& __obj)
+    {
+        __value_ = (*__bin_op)(__value_, __obj.__value);
+    }
+};
+
+// Exclusive scan for other binary operations and types
+template <class _InputIterator, class _Size, class _OutputIterator, class _UnaryOperation, class _Tp,
+          class _BinaryOperation>
+typename std::enable_if<!is_arithmetic_plus<_Tp, _BinaryOperation>::value, std::pair<_OutputIterator, _Tp>>::type
+__simd_scan(_InputIterator __first, _Size __n, _OutputIterator __result, _UnaryOperation __unary_op, _Tp __init,
+            _BinaryOperation __binary_op, /*Inclusive*/ std::false_type)
+{
+    typedef _Combiner<_Tp, _BinaryOperation> _CombinerType;
+    _CombinerType __init_{__init, &__binary_op};
+
+    _PSTL_PRAGMA_DECLARE_REDUCTION(__bin_op, _CombinerType)
+
+    _PSTL_PRAGMA_SIMD_SCAN(__bin_op : __init_)
+    for (_Size __i = 0; __i < __n; ++__i)
+    {
+        __result[__i] = __init_.__value_;
+        _PSTL_PRAGMA_SIMD_EXCLUSIVE_SCAN(__init_)
+        _PSTL_PRAGMA_FORCEINLINE
+        __init_.__value_ = __binary_op(__init_.__value_, __unary_op(__first[__i]));
+    }
+    return std::make_pair(__result + __n, __init_.__value_);
+}
+
+// Inclusive scan for "+" and arithmetic types
+template <class _InputIterator, class _Size, class _OutputIterator, class _UnaryOperation, class _Tp,
+          class _BinaryOperation>
+typename std::enable_if<is_arithmetic_plus<_Tp, _BinaryOperation>::value, std::pair<_OutputIterator, _Tp>>::type
+__simd_scan(_InputIterator __first, _Size __n, _OutputIterator __result, _UnaryOperation __unary_op, _Tp __init,
+            _BinaryOperation, /*Inclusive*/ std::true_type)
+{
+    _PSTL_PRAGMA_SIMD_SCAN(+ : __init)
+    for (_Size __i = 0; __i < __n; ++__i)
+    {
+        __init += __unary_op(__first[__i]);
+        _PSTL_PRAGMA_SIMD_INCLUSIVE_SCAN(__init)
+        __result[__i] = __init;
+    }
+    return std::make_pair(__result + __n, __init);
+}
+
+// Inclusive scan for other binary operations and types
+template <class _InputIterator, class _Size, class _OutputIterator, class _UnaryOperation, class _Tp,
+          class _BinaryOperation>
+typename std::enable_if<!is_arithmetic_plus<_Tp, _BinaryOperation>::value, std::pair<_OutputIterator, _Tp>>::type
+__simd_scan(_InputIterator __first, _Size __n, _OutputIterator __result, _UnaryOperation __unary_op, _Tp __init,
+            _BinaryOperation __binary_op, std::true_type)
+{
+    typedef _Combiner<_Tp, _BinaryOperation> _CombinerType;
+    _CombinerType __init_{__init, &__binary_op};
+
+    _PSTL_PRAGMA_DECLARE_REDUCTION(__bin_op, _CombinerType)
+
+    _PSTL_PRAGMA_SIMD_SCAN(__bin_op : __init_)
+    for (_Size __i = 0; __i < __n; ++__i)
+    {
+        _PSTL_PRAGMA_FORCEINLINE
+        __init_.__value_ = __binary_op(__init_.__value_, __unary_op(__first[__i]));
+        _PSTL_PRAGMA_SIMD_INCLUSIVE_SCAN(__init_)
+        __result[__i] = __init_.__value_;
+    }
+    return std::make_pair(__result + __n, __init_.__value_);
+}
+
+// [restriction] - std::iterator_traits<_ForwardIterator>::value_type should be DefaultConstructible.
+// complexity [violation] - We will have at most (__n-1 + number_of_lanes) comparisons instead of at most __n-1.
+template <typename _ForwardIterator, typename _Size, typename _Compare>
+_ForwardIterator
+__simd_min_element(_ForwardIterator __first, _Size __n, _Compare __comp) noexcept
+{
+    if (__n == 0)
+    {
+        return __first;
+    }
+
+    typedef typename std::iterator_traits<_ForwardIterator>::value_type _ValueType;
+    struct _ComplexType
+    {
+        _ValueType __min_val;
+        _Size __min_ind;
+        _Compare* __min_comp;
+
+        _ComplexType() : __min_val{}, __min_ind{}, __min_comp(nullptr) {}
+        _ComplexType(const _ValueType& val, const _Compare* comp)
+            : __min_val(val), __min_ind(0), __min_comp(const_cast<_Compare*>(comp))
+        {
+        }
+        _ComplexType(const _ComplexType& __obj)
+            : __min_val(__obj.__min_val), __min_ind(__obj.__min_ind), __min_comp(__obj.__min_comp)
+        {
+        }
+
+        _PSTL_PRAGMA_DECLARE_SIMD
+        void
+        operator()(const _ComplexType& __obj)
+        {
+            if (!(*__min_comp)(__min_val, __obj.__min_val) &&
+                ((*__min_comp)(__obj.__min_val, __min_val) || __obj.__min_ind - __min_ind < 0))
+            {
+                __min_val = __obj.__min_val;
+                __min_ind = __obj.__min_ind;
+            }
+        }
+    };
+
+    _ComplexType __init{*__first, &__comp};
+
+    _PSTL_PRAGMA_DECLARE_REDUCTION(__min_func, _ComplexType)
+
+    _PSTL_PRAGMA_SIMD_REDUCTION(__min_func : __init)
+    for (_Size __i = 1; __i < __n; ++__i)
+    {
+        const _ValueType __min_val = __init.__min_val;
+        const _ValueType __current = __first[__i];
+        if (__comp(__current, __min_val))
+        {
+            __init.__min_val = __current;
+            __init.__min_ind = __i;
+        }
+    }
+    return __first + __init.__min_ind;
+}
+
+// [restriction] - std::iterator_traits<_ForwardIterator>::value_type should be DefaultConstructible.
+// complexity [violation] - We will have at most (2*(__n-1) + 4*number_of_lanes) comparisons instead of at most [1.5*(__n-1)].
+template <typename _ForwardIterator, typename _Size, typename _Compare>
+std::pair<_ForwardIterator, _ForwardIterator>
+__simd_minmax_element(_ForwardIterator __first, _Size __n, _Compare __comp) noexcept
+{
+    if (__n == 0)
+    {
+        return std::make_pair(__first, __first);
+    }
+    typedef typename std::iterator_traits<_ForwardIterator>::value_type _ValueType;
+
+    struct _ComplexType
+    {
+        _ValueType __min_val;
+        _ValueType __max_val;
+        _Size __min_ind;
+        _Size __max_ind;
+        _Compare* __minmax_comp;
+
+        _ComplexType() : __min_val{}, __max_val{}, __min_ind{}, __max_ind{}, __minmax_comp(nullptr) {}
+        _ComplexType(const _ValueType& min_val, const _ValueType& max_val, const _Compare* comp)
+            : __min_val(min_val), __max_val(max_val), __min_ind(0), __max_ind(0),
+              __minmax_comp(const_cast<_Compare*>(comp))
+        {
+        }
+        _ComplexType(const _ComplexType& __obj)
+            : __min_val(__obj.__min_val), __max_val(__obj.__max_val), __min_ind(__obj.__min_ind),
+              __max_ind(__obj.__max_ind), __minmax_comp(__obj.__minmax_comp)
+        {
+        }
+
+        void
+        operator()(const _ComplexType& __obj)
+        {
+            // min
+            if ((*__minmax_comp)(__obj.__min_val, __min_val))
+            {
+                __min_val = __obj.__min_val;
+                __min_ind = __obj.__min_ind;
+            }
+            else if (!(*__minmax_comp)(__min_val, __obj.__min_val))
+            {
+                __min_val = __obj.__min_val;
+                __min_ind = (__min_ind - __obj.__min_ind < 0) ? __min_ind : __obj.__min_ind;
+            }
+
+            // max
+            if ((*__minmax_comp)(__max_val, __obj.__max_val))
+            {
+                __max_val = __obj.__max_val;
+                __max_ind = __obj.__max_ind;
+            }
+            else if (!(*__minmax_comp)(__obj.__max_val, __max_val))
+            {
+                __max_val = __obj.__max_val;
+                __max_ind = (__max_ind - __obj.__max_ind < 0) ? __obj.__max_ind : __max_ind;
+            }
+        }
+    };
+
+    _ComplexType __init{*__first, *__first, &__comp};
+
+    _PSTL_PRAGMA_DECLARE_REDUCTION(__min_func, _ComplexType);
+
+    _PSTL_PRAGMA_SIMD_REDUCTION(__min_func : __init)
+    for (_Size __i = 1; __i < __n; ++__i)
+    {
+        auto __min_val = __init.__min_val;
+        auto __max_val = __init.__max_val;
+        auto __current = __first + __i;
+        if (__comp(*__current, __min_val))
+        {
+            __init.__min_val = *__current;
+            __init.__min_ind = __i;
+        }
+        else if (!__comp(*__current, __max_val))
+        {
+            __init.__max_val = *__current;
+            __init.__max_ind = __i;
+        }
+    }
+    return std::make_pair(__first + __init.__min_ind, __first + __init.__max_ind);
+}
+
+template <class _InputIterator, class _DifferenceType, class _OutputIterator1, class _OutputIterator2,
+          class _UnaryPredicate>
+std::pair<_OutputIterator1, _OutputIterator2>
+__simd_partition_copy(_InputIterator __first, _DifferenceType __n, _OutputIterator1 __out_true,
+                      _OutputIterator2 __out_false, _UnaryPredicate __pred) noexcept
+{
+    _DifferenceType __cnt_true = 0, __cnt_false = 0;
+
+    _PSTL_PRAGMA_SIMD
+    for (_DifferenceType __i = 0; __i < __n; ++__i)
+    {
+        _PSTL_PRAGMA_SIMD_ORDERED_MONOTONIC_2ARGS(__cnt_true : 1, __cnt_false : 1)
+        if (__pred(__first[__i]))
+        {
+            __out_true[__cnt_true] = __first[__i];
+            ++__cnt_true;
+        }
+        else
+        {
+            __out_false[__cnt_false] = __first[__i];
+            ++__cnt_false;
+        }
+    }
+    return std::make_pair(__out_true + __cnt_true, __out_false + __cnt_false);
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_ForwardIterator1
+__simd_find_first_of(_ForwardIterator1 __first, _ForwardIterator1 __last, _ForwardIterator2 __s_first,
+                     _ForwardIterator2 __s_last, _BinaryPredicate __pred) noexcept
+{
+    typedef typename std::iterator_traits<_ForwardIterator1>::difference_type _DifferencType;
+
+    const _DifferencType __n1 = __last - __first;
+    const _DifferencType __n2 = __s_last - __s_first;
+    if (__n1 == 0 || __n2 == 0)
+    {
+        return __last; // according to the standard
+    }
+
+    // Common case
+    // If first sequence larger than second then we'll run simd_first with parameters of first sequence.
+    // Otherwise, vice versa.
+    if (__n1 < __n2)
+    {
+        for (; __first != __last; ++__first)
+        {
+            if (__unseq_backend::__simd_or(
+                    __s_first, __n2,
+                    __internal::__equal_value_by_pred<decltype(*__first), _BinaryPredicate>(*__first, __pred)))
+            {
+                return __first;
+            }
+        }
+    }
+    else
+    {
+        for (; __s_first != __s_last; ++__s_first)
+        {
+            const auto __result = __unseq_backend::__simd_first(
+                __first, _DifferencType(0), __n1, [__s_first, &__pred](_ForwardIterator1 __it, _DifferencType __i) {
+                    return __pred(__it[__i], *__s_first);
+                });
+            if (__result != __last)
+            {
+                return __result;
+            }
+        }
+    }
+    return __last;
+}
+
+template <class _RandomAccessIterator, class _DifferenceType, class _UnaryPredicate>
+_RandomAccessIterator
+__simd_remove_if(_RandomAccessIterator __first, _DifferenceType __n, _UnaryPredicate __pred) noexcept
+{
+    // find first element we need to remove
+    auto __current = __unseq_backend::__simd_first(
+        __first, _DifferenceType(0), __n,
+        [&__pred](_RandomAccessIterator __it, _DifferenceType __i) { return __pred(__it[__i]); });
+    __n -= __current - __first;
+
+    // if we have in sequence only one element that pred(__current[1]) != false we can exit the function
+    if (__n < 2)
+    {
+        return __current;
+    }
+
+    _DifferenceType __cnt = 0;
+    _PSTL_PRAGMA_SIMD
+    for (_DifferenceType __i = 1; __i < __n; ++__i)
+    {
+        _PSTL_PRAGMA_SIMD_ORDERED_MONOTONIC(__cnt : 1)
+        if (!__pred(__current[__i]))
+        {
+            __current[__cnt] = std::move(__current[__i]);
+            ++__cnt;
+        }
+    }
+    return __current + __cnt;
+}
+} // namespace __unseq_backend
+} // namespace __pstl
+
+_PSTL_HIDE_FROM_ABI_POP
+
+#endif /* _PSTL_UNSEQ_BACKEND_SIMD_H */
diff --git a/pstl/include/pstl/internal/utils.h b/pstl/include/pstl/internal/utils.h
new file mode 100644
index 0000000..ec9d467
--- /dev/null
+++ b/pstl/include/pstl/internal/utils.h
@@ -0,0 +1,177 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_UTILS_H
+#define _PSTL_UTILS_H
+
+#include <new>
+#include <iterator>
+
+_PSTL_HIDE_FROM_ABI_PUSH
+
+namespace __pstl
+{
+namespace __internal
+{
+
+template <typename _Fp>
+auto
+__except_handler(_Fp __f) -> decltype(__f())
+{
+    try
+    {
+        return __f();
+    }
+    catch (const std::bad_alloc&)
+    {
+        throw; // re-throw bad_alloc according to the standard [algorithms.parallel.exceptions]
+    }
+    catch (...)
+    {
+        std::terminate(); // Good bye according to the standard [algorithms.parallel.exceptions]
+    }
+}
+
+template <typename _Fp>
+void
+__invoke_if(std::true_type, _Fp __f)
+{
+    __f();
+}
+
+template <typename _Fp>
+void __invoke_if(std::false_type, _Fp)
+{
+}
+
+template <typename _Fp>
+void
+__invoke_if_not(std::false_type, _Fp __f)
+{
+    __f();
+}
+
+template <typename _Fp>
+void __invoke_if_not(std::true_type, _Fp)
+{
+}
+
+template <typename _F1, typename _F2>
+auto
+__invoke_if_else(std::true_type, _F1 __f1, _F2) -> decltype(__f1())
+{
+    return __f1();
+}
+
+template <typename _F1, typename _F2>
+auto
+__invoke_if_else(std::false_type, _F1, _F2 __f2) -> decltype(__f2())
+{
+    return __f2();
+}
+
+//! Unary operator that returns reference to its argument.
+struct __no_op
+{
+    template <typename _Tp>
+    _Tp&&
+    operator()(_Tp&& __a) const
+    {
+        return std::forward<_Tp>(__a);
+    }
+};
+
+template <typename _Pred>
+class __reorder_pred
+{
+    _Pred _M_pred;
+
+  public:
+    explicit __reorder_pred(_Pred __pred) : _M_pred(__pred) {}
+
+    template <typename _FTp, typename _STp>
+    bool
+    operator()(_FTp&& __a, _STp&& __b)
+    {
+        return _M_pred(std::forward<_STp>(__b), std::forward<_FTp>(__a));
+    }
+};
+
+//! Like a polymorphic lambda for pred(...,value)
+template <typename _Tp, typename _Predicate>
+class __equal_value_by_pred
+{
+    const _Tp& _M_value;
+    _Predicate _M_pred;
+
+  public:
+    __equal_value_by_pred(const _Tp& __value, _Predicate __pred) : _M_value(__value), _M_pred(__pred) {}
+
+    template <typename _Arg>
+    bool
+    operator()(_Arg&& __arg)
+    {
+        return _M_pred(std::forward<_Arg>(__arg), _M_value);
+    }
+};
+
+//! Like a polymorphic lambda for ==value
+template <typename _Tp>
+class __equal_value
+{
+    const _Tp& _M_value;
+
+  public:
+    explicit __equal_value(const _Tp& __value) : _M_value(__value) {}
+
+    template <typename _Arg>
+    bool
+    operator()(_Arg&& __arg) const
+    {
+        return std::forward<_Arg>(__arg) == _M_value;
+    }
+};
+
+//! Logical negation of ==value
+template <typename _Tp>
+class __not_equal_value
+{
+    const _Tp& _M_value;
+
+  public:
+    explicit __not_equal_value(const _Tp& __value) : _M_value(__value) {}
+
+    template <typename _Arg>
+    bool
+    operator()(_Arg&& __arg) const
+    {
+        return !(std::forward<_Arg>(__arg) == _M_value);
+    }
+};
+
+template <typename _ForwardIterator, typename _Compare>
+_ForwardIterator
+__cmp_iterators_by_values(_ForwardIterator __a, _ForwardIterator __b, _Compare __comp)
+{
+    if (__a < __b)
+    { // we should return closer iterator
+        return __comp(*__b, *__a) ? __b : __a;
+    }
+    else
+    {
+        return __comp(*__a, *__b) ? __a : __b;
+    }
+}
+
+} // namespace __internal
+} // namespace __pstl
+
+_PSTL_HIDE_FROM_ABI_POP
+
+#endif /* _PSTL_UTILS_H */
diff --git a/pstl/test/CMakeLists.txt b/pstl/test/CMakeLists.txt
new file mode 100644
index 0000000..bc027c3
--- /dev/null
+++ b/pstl/test/CMakeLists.txt
@@ -0,0 +1,41 @@
+#===-- CMakeLists.txt ----------------------------------------------------===##
+#
+# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+#
+#===----------------------------------------------------------------------===##
+
+# TODO(ldionne): This CMake testing infrastructure should be replaced with a
+#                llvm-lit test suite.
+
+add_custom_target(pstl-build-tests
+    COMMENT "Build all the pstl tests.")
+
+add_custom_target(check-pstl
+    COMMAND "${CMAKE_CTEST_COMMAND}" --output-on-failure
+    USES_TERMINAL
+    DEPENDS pstl-build-tests
+    COMMENT "Build and run all the unit tests.")
+
+add_library(test_stdlib INTERFACE)
+target_include_directories(test_stdlib INTERFACE "${CMAKE_CURRENT_SOURCE_DIR}/support/stdlib")
+target_link_libraries(test_stdlib INTERFACE pstl::ParallelSTL)
+target_compile_options(test_stdlib INTERFACE -Wno-gnu-include-next)
+
+file(GLOB_RECURSE UNIT_TESTS "*.pass.cpp")
+foreach(_file IN LISTS UNIT_TESTS)
+    file(RELATIVE_PATH _target "${CMAKE_CURRENT_SOURCE_DIR}" "${_file}")
+    string(REPLACE ".cpp" "" _target "${_target}")
+    string(REPLACE "/" "-" _target "${_target}")
+    set(_target "pstl-${_target}")
+
+    add_executable(${_target} EXCLUDE_FROM_ALL "${_file}")
+    target_include_directories(${_target} PRIVATE "${CMAKE_CURRENT_LIST_DIR}")
+    target_compile_options(${_target} PRIVATE -Wno-unused-local-typedef -Wno-unused-variable)
+    target_link_libraries(${_target} PRIVATE test_stdlib)
+    set_target_properties(${_target} PROPERTIES CXX_EXTENSIONS NO
+                                                RUNTIME_OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
+    add_test(${_target} "${CMAKE_CURRENT_BINARY_DIR}/${_target}")
+    add_dependencies(pstl-build-tests ${_target})
+endforeach()
diff --git a/pstl/test/pstl/header_inclusion_order_algorithm_0.pass.cpp b/pstl/test/pstl/header_inclusion_order_algorithm_0.pass.cpp
new file mode 100644
index 0000000..8cdeb18
--- /dev/null
+++ b/pstl/test/pstl/header_inclusion_order_algorithm_0.pass.cpp
@@ -0,0 +1,21 @@
+// -*- C++ -*-
+//===-- header_inclusion_order_algorithm_0.pass.cpp -----------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+int
+main()
+{
+    return 0;
+}
diff --git a/pstl/test/pstl/header_inclusion_order_algorithm_1.pass.cpp b/pstl/test/pstl/header_inclusion_order_algorithm_1.pass.cpp
new file mode 100644
index 0000000..ea6c4f4
--- /dev/null
+++ b/pstl/test/pstl/header_inclusion_order_algorithm_1.pass.cpp
@@ -0,0 +1,21 @@
+// -*- C++ -*-
+//===-- header_inclusion_order_algorithm_1.pass.cpp -----------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <algorithm>
+#include <execution>
+
+int
+main()
+{
+    return 0;
+}
diff --git a/pstl/test/pstl/header_inclusion_order_memory_0.pass.cpp b/pstl/test/pstl/header_inclusion_order_memory_0.pass.cpp
new file mode 100644
index 0000000..dbb70c5
--- /dev/null
+++ b/pstl/test/pstl/header_inclusion_order_memory_0.pass.cpp
@@ -0,0 +1,21 @@
+// -*- C++ -*-
+//===-- header_inclusion_order_memory_0.pass.cpp --------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <memory>
+
+int
+main()
+{
+    return 0;
+}
diff --git a/pstl/test/pstl/header_inclusion_order_memory_1.pass.cpp b/pstl/test/pstl/header_inclusion_order_memory_1.pass.cpp
new file mode 100644
index 0000000..99f059c
--- /dev/null
+++ b/pstl/test/pstl/header_inclusion_order_memory_1.pass.cpp
@@ -0,0 +1,21 @@
+// -*- C++ -*-
+//===-- header_inclusion_order_memory_1.pass.cpp --------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <memory>
+#include <execution>
+
+int
+main()
+{
+    return 0;
+}
diff --git a/pstl/test/pstl/header_inclusion_order_numeric_0.pass.cpp b/pstl/test/pstl/header_inclusion_order_numeric_0.pass.cpp
new file mode 100644
index 0000000..4b18657
--- /dev/null
+++ b/pstl/test/pstl/header_inclusion_order_numeric_0.pass.cpp
@@ -0,0 +1,21 @@
+// -*- C++ -*-
+//===-- header_inclusion_order_numeric_0.pass.cpp -------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <numeric>
+
+int
+main()
+{
+    return 0;
+}
diff --git a/pstl/test/pstl/header_inclusion_order_numeric_1.pass.cpp b/pstl/test/pstl/header_inclusion_order_numeric_1.pass.cpp
new file mode 100644
index 0000000..a0bb24e
--- /dev/null
+++ b/pstl/test/pstl/header_inclusion_order_numeric_1.pass.cpp
@@ -0,0 +1,21 @@
+// -*- C++ -*-
+//===-- header_inclusion_order_numeric_0.pass.cpp -------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <numeric>
+#include <execution>
+
+int
+main()
+{
+    return 0;
+}
diff --git a/pstl/test/pstl/version.pass.cpp b/pstl/test/pstl/version.pass.cpp
new file mode 100644
index 0000000..820dabc
--- /dev/null
+++ b/pstl/test/pstl/version.pass.cpp
@@ -0,0 +1,20 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <pstl/internal/pstl_config.h>
+
+static_assert(_PSTL_VERSION == 17000);
+static_assert(_PSTL_VERSION_MAJOR == 17);
+static_assert(_PSTL_VERSION_MINOR == 00);
+static_assert(_PSTL_VERSION_PATCH == 0);
+
+int
+main()
+{
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.merge/inplace_merge.pass.cpp b/pstl/test/std/algorithms/alg.merge/inplace_merge.pass.cpp
new file mode 100644
index 0000000..3446d95
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.merge/inplace_merge.pass.cpp
@@ -0,0 +1,159 @@
+// -*- C++ -*-
+//===-- inplace_merge.pass.cpp --------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct test_one_policy
+{
+#if defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) ||                                                             \
+    defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) // dummy specialization by policy type, in case of broken configuration
+    template <typename BiDirIt1, typename Size, typename Generator1, typename Generator2, typename Compare>
+    void
+    operator()(pstl::execution::unsequenced_policy, BiDirIt1 first1, BiDirIt1 last1, BiDirIt1 first2, BiDirIt1 last2,
+               Size n, Size m, Generator1 generator1, Generator2 generator2, Compare comp)
+    {
+    }
+
+    template <typename BiDirIt1, typename Size, typename Generator1, typename Generator2, typename Compare>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, BiDirIt1 first1, BiDirIt1 last1, BiDirIt1 first2,
+               BiDirIt1 last2, Size n, Size m, Generator1 generator1, Generator2 generator2, Compare comp)
+    {
+    }
+#endif
+
+    // inplace_merge works with bidirectional iterators at least
+    template <typename Policy, typename BiDirIt1, typename Size, typename Generator1, typename Generator2,
+              typename Compare>
+    typename std::enable_if<!is_same_iterator_category<BiDirIt1, std::forward_iterator_tag>::value, void>::type
+    operator()(Policy&& exec, BiDirIt1 first1, BiDirIt1 last1, BiDirIt1 first2, BiDirIt1 last2, Size n, Size m,
+               Generator1 generator1, Generator2 generator2, Compare comp)
+    {
+        const BiDirIt1 mid1 = std::next(first1, m);
+        fill_data(first1, mid1, generator1);
+        fill_data(mid1, last1, generator2);
+
+        const BiDirIt1 mid2 = std::next(first2, m);
+        fill_data(first2, mid2, generator1);
+        fill_data(mid2, last2, generator2);
+
+        std::inplace_merge(first1, mid1, last1, comp);
+        std::inplace_merge(exec, first2, mid2, last2, comp);
+        EXPECT_EQ_N(first1, first2, n, "wrong effect from inplace_merge with predicate");
+    }
+
+    template <typename Policy, typename BiDirIt1, typename Size, typename Generator1, typename Generator2,
+              typename Compare>
+    typename std::enable_if<is_same_iterator_category<BiDirIt1, std::forward_iterator_tag>::value, void>::type
+    operator()(Policy&&, BiDirIt1, BiDirIt1, BiDirIt1, BiDirIt1, Size, Size, Generator1, Generator2, Compare)
+    {
+    }
+};
+
+template <typename T, typename Generator1, typename Generator2, typename Compare>
+void
+test_by_type(Generator1 generator1, Generator2 generator2, Compare comp)
+{
+    using namespace std;
+    size_t max_size = 100000;
+    Sequence<T> in1(max_size, [](size_t v) { return T(v); });
+    Sequence<T> exp(max_size, [](size_t v) { return T(v); });
+    size_t m;
+
+    for (size_t n = 0; n <= max_size; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        m = 0;
+        invoke_on_all_policies(test_one_policy(), in1.begin(), in1.begin() + n, exp.begin(), exp.begin() + n, n, m,
+                               generator1, generator2, comp);
+
+        m = n / 3;
+        invoke_on_all_policies(test_one_policy(), in1.begin(), in1.begin() + n, exp.begin(), exp.begin() + n, n, m,
+                               generator1, generator2, comp);
+
+        m = 2 * n / 3;
+        invoke_on_all_policies(test_one_policy(), in1.begin(), in1.begin() + n, exp.begin(), exp.begin() + n, n, m,
+                               generator1, generator2, comp);
+    }
+}
+
+template <typename T>
+struct LocalWrapper
+{
+    explicit LocalWrapper(int32_t k) : my_val(k) {}
+    LocalWrapper(LocalWrapper&& input) { my_val = std::move(input.my_val); }
+    LocalWrapper&
+    operator=(LocalWrapper&& input)
+    {
+        my_val = std::move(input.my_val);
+        return *this;
+    }
+    bool
+    operator<(const LocalWrapper<T>& w) const
+    {
+        return my_val < w.my_val;
+    }
+    friend bool
+    operator==(const LocalWrapper<T>& x, const LocalWrapper<T>& y)
+    {
+        return x.my_val == y.my_val;
+    }
+    friend std::ostream&
+    operator<<(std::ostream& stream, const LocalWrapper<T>& input)
+    {
+        return stream << input.my_val;
+    }
+
+  private:
+    T my_val;
+};
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator iter)
+    {
+        invoke_if(exec, [&]() { inplace_merge(exec, iter, iter, iter, non_const(std::less<T>())); });
+    }
+};
+
+int
+main()
+{
+    test_by_type<float64_t>([](int32_t i) { return -2 * i; }, [](int32_t i) { return -(2 * i + 1); },
+                            [](const float64_t x, const float64_t y) { return x > y; });
+
+    test_by_type<int32_t>([](int32_t i) { return 10 * i; }, [](int32_t i) { return i + 1; }, std::less<int32_t>());
+
+    test_by_type<LocalWrapper<float32_t>>([](int32_t i) { return LocalWrapper<float32_t>(2 * i + 1); },
+                                          [](int32_t i) { return LocalWrapper<float32_t>(2 * i); },
+                                          std::less<LocalWrapper<float32_t>>());
+
+    test_algo_basic_single<int32_t>(run_for_rnd_bi<test_non_const<int32_t>>());
+
+    test_by_type<MemoryChecker>(
+        [](std::size_t idx){ return MemoryChecker{std::int32_t(idx * 2)}; },
+        [](std::size_t idx){ return MemoryChecker{std::int32_t(idx * 2 + 1)}; },
+        [](const MemoryChecker& val1, const MemoryChecker& val2){ return val1.value() == val2.value(); });
+    EXPECT_FALSE(MemoryChecker::alive_objects() < 0, "wrong effect from inplace_merge: number of ctors calls < num of dtors calls");
+    EXPECT_FALSE(MemoryChecker::alive_objects() > 0, "wrong effect from inplace_merge: number of ctors calls > num of dtors calls");
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.merge/merge.pass.cpp b/pstl/test/std/algorithms/alg.merge/merge.pass.cpp
new file mode 100644
index 0000000..a09ef42
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.merge/merge.pass.cpp
@@ -0,0 +1,113 @@
+// -*- C++ -*-
+//===-- merge.pass.cpp ----------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+#include <functional>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct test_merge
+{
+    template <typename Policy, typename InputIterator1, typename InputIterator2, typename OutputIterator,
+              typename Compare>
+    void
+    operator()(Policy&& exec, InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2,
+               OutputIterator out_first, OutputIterator out_last, Compare comp)
+    {
+        using namespace std;
+        {
+            const auto res = merge(exec, first1, last1, first2, last2, out_first, comp);
+            EXPECT_TRUE(res == out_last, "wrong return result from merge with predicate");
+            EXPECT_TRUE(is_sorted(out_first, res, comp), "wrong result from merge with predicate");
+            EXPECT_TRUE(includes(out_first, res, first1, last1, comp), "first sequence is not a part of result");
+            EXPECT_TRUE(includes(out_first, res, first2, last2, comp), "second sequence is not a part of result");
+        }
+        {
+            const auto res = merge(exec, first1, last1, first2, last2, out_first);
+            EXPECT_TRUE(res == out_last, "wrong return result from merge");
+            EXPECT_TRUE(is_sorted(out_first, res), "wrong result from merge");
+        }
+    }
+
+    // for reverse iterators
+    template <typename Policy, typename InputIterator1, typename InputIterator2, typename OutputIterator,
+              typename Compare>
+    void
+    operator()(Policy&& exec, std::reverse_iterator<InputIterator1> first1, std::reverse_iterator<InputIterator1> last1,
+               std::reverse_iterator<InputIterator2> first2, std::reverse_iterator<InputIterator2> last2,
+               std::reverse_iterator<OutputIterator> out_first, std::reverse_iterator<OutputIterator> out_last, Compare)
+    {
+        using namespace std;
+        typedef typename std::iterator_traits<std::reverse_iterator<InputIterator1>>::value_type T;
+        const auto res = merge(exec, first1, last1, first2, last2, out_first, std::greater<T>());
+
+        EXPECT_TRUE(res == out_last, "wrong return result from merge with predicate");
+        EXPECT_TRUE(is_sorted(out_first, res, std::greater<T>()), "wrong result from merge with predicate");
+        EXPECT_TRUE(includes(out_first, res, first1, last1, std::greater<T>()),
+                    "first sequence is not a part of result");
+        EXPECT_TRUE(includes(out_first, res, first2, last2, std::greater<T>()),
+                    "second sequence is not a part of result");
+    }
+};
+
+template <typename T, typename Generator1, typename Generator2>
+void
+test_merge_by_type(Generator1 generator1, Generator2 generator2)
+{
+    using namespace std;
+    size_t max_size = 100000;
+    Sequence<T> in1(max_size, generator1);
+    Sequence<T> in2(max_size / 2, generator2);
+    Sequence<T> out(in1.size() + in2.size());
+    std::sort(in1.begin(), in1.end());
+    std::sort(in2.begin(), in2.end());
+
+    for (size_t size = 0; size <= max_size; size = size <= 16 ? size + 1 : size_t(3.1415 * size))
+    {
+        invoke_on_all_policies(test_merge(), in1.cbegin(), in1.cbegin() + size, in2.data(), in2.data() + size / 2,
+                               out.begin(), out.begin() + 1.5 * size, std::less<T>());
+        invoke_on_all_policies(test_merge(), in1.data(), in1.data() + size, in2.cbegin(), in2.cbegin() + size / 2,
+                               out.begin(), out.begin() + 3 * size / 2, std::less<T>());
+    }
+}
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename InputIterator, typename OutputIterator>
+    void
+    operator()(Policy&& exec, InputIterator input_iter, OutputIterator out_iter)
+    {
+        merge(exec, input_iter, input_iter, input_iter, input_iter, out_iter, non_const(std::less<T>()));
+    }
+};
+
+int
+main()
+{
+    test_merge_by_type<int32_t>([](size_t v) { return (v % 2 == 0 ? v : -v) * 3; }, [](size_t v) { return v * 2; });
+    test_merge_by_type<float64_t>([](size_t v) { return float64_t(v); }, [](size_t v) { return float64_t(v - 100); });
+
+#if !defined(_PSTL_ICC_16_17_TEST_64_TIMEOUT)
+    test_merge_by_type<Wrapper<int16_t>>([](size_t v) { return Wrapper<int16_t>(v % 100); },
+                                         [](size_t v) { return Wrapper<int16_t>(v % 10); });
+#endif
+
+    test_algo_basic_double<int32_t>(run_for_rnd_fw<test_non_const<int32_t>>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.modifying.operations/alg.copy/copy_if.pass.cpp b/pstl/test/std/algorithms/alg.modifying.operations/alg.copy/copy_if.pass.cpp
new file mode 100644
index 0000000..692907e
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.modifying.operations/alg.copy/copy_if.pass.cpp
@@ -0,0 +1,147 @@
+// -*- C++ -*-
+//===-- copy_if.pass.cpp --------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+// Tests for copy_if and remove_copy_if
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct run_copy_if
+{
+#if defined(_PSTL_ICC_16_VC14_TEST_PAR_TBB_RT_RELEASE_64_BROKEN) // dummy specializations to skip testing in case of broken configuration
+    template <typename InputIterator, typename OutputIterator, typename OutputIterator2, typename Size,
+              typename Predicate, typename T>
+    void
+    operator()(pstl::execution::parallel_policy, InputIterator first, InputIterator last, OutputIterator out_first,
+               OutputIterator out_last, OutputIterator2 expected_first, OutputIterator2 expected_last, Size n,
+               Predicate pred, T trash)
+    {
+    }
+    template <typename InputIterator, typename OutputIterator, typename OutputIterator2, typename Size,
+              typename Predicate, typename T>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, InputIterator first, InputIterator last,
+               OutputIterator out_first, OutputIterator out_last, OutputIterator2 expected_first,
+               OutputIterator2 expected_last, Size n, Predicate pred, T trash)
+    {
+    }
+#endif
+
+    template <typename Policy, typename InputIterator, typename OutputIterator, typename OutputIterator2, typename Size,
+              typename Predicate, typename T>
+    void
+    operator()(Policy&& exec, InputIterator first, InputIterator last, OutputIterator out_first,
+               OutputIterator out_last, OutputIterator2 expected_first, OutputIterator2, Size n, Predicate pred,
+               T trash)
+    {
+        // Cleaning
+        std::fill_n(expected_first, n, trash);
+        std::fill_n(out_first, n, trash);
+
+        // Run copy_if
+        auto i = copy_if(first, last, expected_first, pred);
+        auto k = copy_if(exec, first, last, out_first, pred);
+        EXPECT_EQ_N(expected_first, out_first, n, "wrong copy_if effect");
+        for (size_t j = 0; j < GuardSize; ++j)
+        {
+            ++k;
+        }
+        EXPECT_TRUE(out_last == k, "wrong return value from copy_if");
+
+        // Cleaning
+        std::fill_n(expected_first, n, trash);
+        std::fill_n(out_first, n, trash);
+        // Run remove_copy_if
+        i = remove_copy_if(first, last, expected_first, [=](const T& x) { return !pred(x); });
+        k = remove_copy_if(exec, first, last, out_first, [=](const T& x) { return !pred(x); });
+        EXPECT_EQ_N(expected_first, out_first, n, "wrong remove_copy_if effect");
+        for (size_t j = 0; j < GuardSize; ++j)
+        {
+            ++k;
+        }
+        EXPECT_TRUE(out_last == k, "wrong return value from remove_copy_if");
+    }
+};
+
+template <typename T, typename Predicate, typename Convert>
+void
+test(T trash, Predicate pred, Convert convert, bool check_weakness = true)
+{
+    // Try sequences of various lengths.
+    for (size_t n = 0; n <= 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        // count is number of output elements, plus a handful
+        // more for sake of detecting buffer overruns.
+        size_t count = GuardSize;
+        Sequence<T> in(n, [&](size_t k) -> T {
+            T val = convert(n ^ k);
+            count += pred(val) ? 1 : 0;
+            return val;
+        });
+
+        Sequence<T> out(count, [=](size_t) { return trash; });
+        Sequence<T> expected(count, [=](size_t) { return trash; });
+        if (check_weakness)
+        {
+            auto expected_result = copy_if(in.cfbegin(), in.cfend(), expected.begin(), pred);
+            size_t m = expected_result - expected.begin();
+            EXPECT_TRUE(n / 4 <= m && m <= 3 * (n + 1) / 4, "weak test for copy_if");
+        }
+        invoke_on_all_policies(run_copy_if(), in.begin(), in.end(), out.begin(), out.end(), expected.begin(),
+                               expected.end(), count, pred, trash);
+        invoke_on_all_policies(run_copy_if(), in.cbegin(), in.cend(), out.begin(), out.end(), expected.begin(),
+                               expected.end(), count, pred, trash);
+    }
+}
+
+struct test_non_const
+{
+    template <typename Policy, typename InputIterator, typename OutputInterator>
+    void
+    operator()(Policy&& exec, InputIterator input_iter, OutputInterator out_iter)
+    {
+        auto is_even = [&](float64_t v) {
+            uint32_t i = (uint32_t)v;
+            return i % 2 == 0;
+        };
+        copy_if(exec, input_iter, input_iter, out_iter, non_const(is_even));
+
+        invoke_if(exec, [&]() { remove_copy_if(exec, input_iter, input_iter, out_iter, non_const(is_even)); });
+    }
+};
+
+int
+main()
+{
+    test<float64_t>(-666.0, [](const float64_t& x) { return x * x <= 1024; },
+                    [](size_t j) { return ((j + 1) % 7 & 2) != 0 ? float64_t(j % 32) : float64_t(j % 33 + 34); });
+
+    test<int32_t>(-666, [](const int32_t& x) { return x != 42; },
+                  [](size_t j) { return ((j + 1) % 5 & 2) != 0 ? int32_t(j + 1) : 42; });
+
+#if !defined(_PSTL_ICC_17_TEST_MAC_RELEASE_32_BROKEN)
+    test<Number>(Number(42, OddTag()), IsMultiple(3, OddTag()), [](int32_t j) { return Number(j, OddTag()); });
+#endif
+
+#if !defined(_PSTL_ICC_16_17_TEST_REDUCTION_RELEASE_BROKEN)
+    test<int32_t>(-666, [](const int32_t&) { return true; }, [](size_t j) { return j; }, false);
+#endif
+
+    test_algo_basic_double<int32_t>(run_for_rnd_fw<test_non_const>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.modifying.operations/alg.partitions/is_partitioned.pass.cpp b/pstl/test/std/algorithms/alg.modifying.operations/alg.partitions/is_partitioned.pass.cpp
new file mode 100644
index 0000000..bd6b259
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.modifying.operations/alg.partitions/is_partitioned.pass.cpp
@@ -0,0 +1,101 @@
+// -*- C++ -*-
+//===-- is_partitioned.pass.cpp -------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct test_one_policy
+{
+    //dummy specialization by policy type, in case of broken configuration
+#if defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) || defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN)
+
+    template <typename Iterator1, typename Predicate>
+    void
+    operator()(pstl::execution::unsequenced_policy, Iterator1 begin1, Iterator1 end1, Predicate pred)
+    {
+    }
+    template <typename Iterator1, typename Predicate>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, Iterator1 begin1, Iterator1 end1, Predicate pred)
+    {
+    }
+#endif
+
+    template <typename ExecutionPolicy, typename Iterator1, typename Predicate>
+    void
+    operator()(ExecutionPolicy&& exec, Iterator1 begin1, Iterator1 end1, Predicate pred)
+    {
+        const bool expected = std::is_partitioned(begin1, end1, pred);
+        const bool actual = std::is_partitioned(exec, begin1, end1, pred);
+        EXPECT_TRUE(actual == expected, "wrong return result from is_partitioned");
+    }
+};
+
+template <typename T, typename Predicate>
+void
+test(Predicate pred)
+{
+
+    const std::size_t max_n = 1000000;
+    Sequence<T> in(max_n, [](std::size_t k) { return T(k); });
+
+    for (std::size_t n1 = 0; n1 <= max_n; n1 = n1 <= 16 ? n1 + 1 : std::size_t(3.1415 * n1))
+    {
+        invoke_on_all_policies(test_one_policy(), in.begin(), in.begin() + n1, pred);
+        std::partition(in.begin(), in.begin() + n1, pred);
+        invoke_on_all_policies(test_one_policy(), in.cbegin(), in.cbegin() + n1, pred);
+    }
+}
+
+template <typename T>
+struct LocalWrapper
+{
+    explicit LocalWrapper(std::size_t k) : my_val(k) {}
+
+  private:
+    T my_val;
+};
+
+struct test_non_const
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator iter)
+    {
+        auto is_even = [&](float64_t v) {
+            uint32_t i = (uint32_t)v;
+            return i % 2 == 0;
+        };
+        invoke_if(exec, [&]() { is_partitioned(exec, iter, iter, non_const(is_even)); });
+    }
+};
+
+int
+main()
+{
+    test<float64_t>([](const float64_t x) { return x < 0; });
+    test<int32_t>([](const int32_t x) { return x > 1000; });
+    test<uint16_t>([](const uint16_t x) { return x % 5 < 3; });
+#if !defined(_PSTL_ICC_18_TEST_EARLY_EXIT_MONOTONIC_RELEASE_BROKEN) && !defined(_PSTL_ICC_19_TEST_IS_PARTITIONED_RELEASE_BROKEN)
+    test<LocalWrapper<float64_t>>([](const LocalWrapper<float64_t>&) { return true; });
+#endif
+
+    test_algo_basic_single<int32_t>(run_for_rnd_fw<test_non_const>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.modifying.operations/alg.partitions/partition.pass.cpp b/pstl/test/std/algorithms/alg.modifying.operations/alg.partitions/partition.pass.cpp
new file mode 100644
index 0000000..724f0ba
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.modifying.operations/alg.partitions/partition.pass.cpp
@@ -0,0 +1,178 @@
+// -*- C++ -*-
+//===-- partition.pass.cpp ------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+// Tests for stable_partition and partition
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+#include <iterator>
+#include <type_traits>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+template <typename T>
+struct DataType
+{
+    explicit DataType(int32_t k) : my_val(k) {}
+    DataType(DataType&& input) { my_val = std::move(input.my_val); }
+    DataType&
+    operator=(DataType&& input)
+    {
+        my_val = std::move(input.my_val);
+        return *this;
+    }
+    T
+    get_val() const
+    {
+        return my_val;
+    }
+
+    friend std::ostream&
+    operator<<(std::ostream& stream, const DataType<T>& input)
+    {
+        return stream << input.my_val;
+    }
+
+  private:
+    T my_val;
+};
+
+template <typename Iterator>
+typename std::enable_if<std::is_trivial<typename std::iterator_traits<Iterator>::value_type>::value, bool>::type
+is_equal(Iterator first, Iterator last, Iterator d_first)
+{
+    return std::equal(first, last, d_first);
+}
+
+template <typename Iterator>
+typename std::enable_if<!std::is_trivial<typename std::iterator_traits<Iterator>::value_type>::value, bool>::type
+    is_equal(Iterator, Iterator, Iterator)
+{
+    return true;
+}
+
+struct test_one_policy
+{
+#if defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) ||                                                             \
+    defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) //dummy specializations to skip testing in case of broken configuration
+    template <typename BiDirIt, typename Size, typename UnaryOp, typename Generator>
+    void
+    operator()(pstl::execution::unsequenced_policy, BiDirIt first, BiDirIt last, BiDirIt exp_first, BiDirIt exp_last,
+               Size n, UnaryOp unary_op, Generator generator)
+    {
+    }
+
+    template <typename BiDirIt, typename Size, typename UnaryOp, typename Generator>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, BiDirIt first, BiDirIt last, BiDirIt exp_first,
+               BiDirIt exp_last, Size n, UnaryOp unary_op, Generator generator)
+    {
+    }
+#elif defined(_PSTL_ICC_16_VC14_TEST_PAR_TBB_RT_RELEASE_64_BROKEN) //dummy specializations to skip testing in case of broken configuration
+    template <typename BiDirIt, typename Size, typename UnaryOp, typename Generator>
+    void
+    operator()(pstl::execution::parallel_policy, BiDirIt first, BiDirIt last, BiDirIt exp_first, BiDirIt exp_last,
+               Size n, UnaryOp unary_op, Generator generator)
+    {
+    }
+
+    template <typename BiDirIt, typename Size, typename UnaryOp, typename Generator>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, BiDirIt first, BiDirIt last, BiDirIt exp_first,
+               BiDirIt exp_last, Size n, UnaryOp unary_op, Generator generator)
+    {
+    }
+#endif
+
+    template <typename Policy, typename BiDirIt, typename Size, typename UnaryOp, typename Generator>
+    typename std::enable_if<!is_same_iterator_category<BiDirIt, std::forward_iterator_tag>::value, void>::type
+    operator()(Policy&& exec, BiDirIt first, BiDirIt last, BiDirIt exp_first, BiDirIt exp_last, Size, UnaryOp unary_op,
+               Generator generator)
+    {
+        // partition
+        {
+            fill_data(first, last, generator);
+            BiDirIt actual_ret = std::partition(exec, first, last, unary_op);
+            EXPECT_TRUE(std::all_of(first, actual_ret, unary_op) && !std::any_of(actual_ret, last, unary_op),
+                        "wrong effect from partition");
+        }
+        // stable_partition
+        {
+            fill_data(exp_first, exp_last, generator);
+            BiDirIt exp_ret = std::stable_partition(exp_first, exp_last, unary_op);
+            fill_data(first, last, generator);
+            BiDirIt actual_ret = std::stable_partition(exec, first, last, unary_op);
+
+            EXPECT_TRUE(std::distance(first, actual_ret) == std::distance(exp_first, exp_ret),
+                        "wrong result from stable_partition");
+            EXPECT_TRUE((is_equal<BiDirIt>(exp_first, exp_last, first)), "wrong effect from stable_partition");
+        }
+    }
+    template <typename Policy, typename BiDirIt, typename Size, typename UnaryOp, typename Generator>
+    typename std::enable_if<is_same_iterator_category<BiDirIt, std::forward_iterator_tag>::value, void>::type
+    operator()(Policy&&, BiDirIt, BiDirIt, BiDirIt, BiDirIt, Size, UnaryOp, Generator)
+    {
+    }
+};
+
+template <typename T, typename Generator, typename UnaryPred>
+void
+test_by_type(Generator generator, UnaryPred pred)
+{
+
+    using namespace std;
+    size_t max_size = 100000;
+    Sequence<T> in(max_size, [](size_t v) { return T(v); });
+    Sequence<T> exp(max_size, [](size_t v) { return T(v); });
+
+    for (size_t n = 0; n <= max_size; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        invoke_on_all_policies(test_one_policy(), in.begin(), in.begin() + n, exp.begin(), exp.begin() + n, n, pred,
+                               generator);
+    }
+}
+
+struct test_non_const
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator iter)
+    {
+        auto is_even = [&](float64_t v) {
+            uint32_t i = (uint32_t)v;
+            return i % 2 == 0;
+        };
+        invoke_if(exec, [&]() {
+            partition(exec, iter, iter, non_const(is_even));
+            stable_partition(exec, iter, iter, non_const(is_even));
+        });
+    }
+};
+
+int
+main()
+{
+#if !defined(_PSTL_ICC_16_17_TEST_REDUCTION_RELEASE_BROKEN)
+    test_by_type<int32_t>([](int32_t i) { return i; }, [](int32_t) { return true; });
+#endif
+    test_by_type<float64_t>([](int32_t i) { return -i; }, [](const float64_t x) { return x < 0; });
+    test_by_type<int64_t>([](int32_t i) { return i + 1; }, [](int64_t x) { return x % 3 == 0; });
+    test_by_type<DataType<float32_t>>([](int32_t i) { return DataType<float32_t>(2 * i + 1); },
+                                      [](const DataType<float32_t>& x) { return x.get_val() < 0; });
+
+    test_algo_basic_single<int32_t>(run_for_rnd_bi<test_non_const>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.modifying.operations/alg.partitions/partition_copy.pass.cpp b/pstl/test/std/algorithms/alg.modifying.operations/alg.partitions/partition_copy.pass.cpp
new file mode 100644
index 0000000..c621f83
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.modifying.operations/alg.partitions/partition_copy.pass.cpp
@@ -0,0 +1,116 @@
+// -*- C++ -*-
+//===-- partition_copy.pass.cpp -------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+// Tests for stable_partition and partition_copy
+#include "support/pstl_test_config.h"
+
+#include <algorithm>
+#include <cstdlib>
+#include <execution>
+#include <functional>
+#include <iterator>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct test_partition_copy
+{
+    template <typename Policy, typename InputIterator, typename OutputIterator, typename OutputIterator2,
+              typename UnaryOp>
+    void
+    operator()(Policy&& exec, InputIterator first, InputIterator last, OutputIterator true_first, OutputIterator,
+               OutputIterator2 false_first, OutputIterator2, UnaryOp unary_op)
+    {
+
+        auto actual_ret = std::partition_copy(exec, first, last, true_first, false_first, unary_op);
+
+        EXPECT_TRUE(std::distance(true_first, actual_ret.first) == std::count_if(first, last, unary_op),
+                    "partition_copy has wrong effect from true sequence");
+        EXPECT_TRUE(std::distance(false_first, actual_ret.second) == std::count_if(first, last, std::not_fn(unary_op)),
+                    "partition_copy has wrong effect from false sequence");
+    }
+
+    //dummy specialization by iterator type and policy type, in case of broken configuration
+#if defined(_PSTL_ICC_1800_TEST_MONOTONIC_RELEASE_64_BROKEN)
+    template <typename InputIterator, typename OutputIterator, typename OutputIterator2, typename UnaryOp>
+    void
+    operator()(pstl::execution::unsequenced_policy, std::reverse_iterator<InputIterator> first,
+               std::reverse_iterator<InputIterator> last, std::reverse_iterator<OutputIterator> true_first,
+               std::reverse_iterator<OutputIterator> true_last, std::reverse_iterator<OutputIterator2> false_first,
+               OutputIterator2 false_last, UnaryOp unary_op)
+    {
+    }
+    template <typename InputIterator, typename OutputIterator, typename OutputIterator2, typename UnaryOp>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, std::reverse_iterator<InputIterator> first,
+               std::reverse_iterator<InputIterator> last, std::reverse_iterator<OutputIterator> true_first,
+               std::reverse_iterator<OutputIterator> true_last, std::reverse_iterator<OutputIterator2> false_first,
+               OutputIterator2 false_last, UnaryOp unary_op)
+    {
+    }
+#endif
+};
+
+template <typename T, typename UnaryPred>
+void
+test(UnaryPred pred)
+{
+
+    const std::size_t max_size = 100000;
+    Sequence<T> in(max_size, [](std::size_t v) -> T { return T(v); });
+    Sequence<T> actual_true(max_size);
+    Sequence<T> actual_false(max_size);
+    for (std::size_t n = 0; n <= max_size; n = n <= 16 ? n + 1 : std::size_t(3.1415 * n))
+    {
+
+        // for non-const input iterators
+        invoke_on_all_policies(test_partition_copy(), in.begin(), in.begin() + n, actual_true.begin(),
+                               actual_true.begin() + n, actual_false.begin(), actual_false.begin() + n, pred);
+
+        // for const input iterators
+        invoke_on_all_policies(test_partition_copy(), in.cbegin(), in.cbegin() + n, actual_true.begin(),
+                               actual_true.begin() + n, actual_false.begin(), actual_false.begin() + n, pred);
+    }
+}
+
+struct test_non_const
+{
+    template <typename Policy, typename InputIterator, typename OutputInterator>
+    void
+    operator()(Policy&& exec, InputIterator input_iter, OutputInterator out_iter)
+    {
+        auto is_even = [&](float64_t v) {
+            uint32_t i = (uint32_t)v;
+            return i % 2 == 0;
+        };
+
+        partition_copy(exec, input_iter, input_iter, out_iter, out_iter, non_const(is_even));
+    }
+};
+
+int
+main()
+{
+    test<int32_t>([](const int32_t value) { return value % 2; });
+
+#if !defined(_PSTL_ICC_16_17_TEST_REDUCTION_RELEASE_BROKEN)
+    test<int32_t>([](const int32_t) { return true; });
+#endif
+
+    test<float64_t>([](const float64_t value) { return value > 2 << 6; });
+    test<Wrapper<float64_t>>([](const Wrapper<float64_t>& value) -> bool { return value.get_my_field() != nullptr; });
+
+    test_algo_basic_double<int32_t>(run_for_rnd_bi<test_non_const>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.modifying.operations/alg.reverse/reverse.pass.cpp b/pstl/test/std/algorithms/alg.modifying.operations/alg.reverse/reverse.pass.cpp
new file mode 100644
index 0000000..126454f
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.modifying.operations/alg.reverse/reverse.pass.cpp
@@ -0,0 +1,104 @@
+// -*- C++ -*-
+//===-- reverse.pass.cpp --------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <iterator>
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct test_one_policy
+{
+#if defined(_PSTL_ICC_18_VC141_TEST_SIMD_LAMBDA_RELEASE_BROKEN) || defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) ||       \
+    defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) // dummy specialization by policy type, in case of broken configuration
+    template <typename Iterator1, typename Iterator2>
+    typename std::enable_if<is_same_iterator_category<Iterator1, std::random_access_iterator_tag>::value, void>::type
+    operator()(pstl::execution::unsequenced_policy, Iterator1 data_b, Iterator1 data_e, Iterator2 actual_b,
+               Iterator2 actual_e)
+    {
+    }
+    template <typename Iterator1, typename Iterator2>
+    typename std::enable_if<is_same_iterator_category<Iterator1, std::random_access_iterator_tag>::value, void>::type
+    operator()(pstl::execution::parallel_unsequenced_policy, Iterator1 data_b, Iterator1 data_e, Iterator2 actual_b,
+               Iterator2 actual_e)
+    {
+    }
+#endif
+
+    template <typename ExecutionPolicy, typename Iterator1, typename Iterator2>
+    typename std::enable_if<!is_same_iterator_category<Iterator1, std::forward_iterator_tag>::value>::type
+    operator()(ExecutionPolicy&& exec, Iterator1 data_b, Iterator1 data_e, Iterator2 actual_b, Iterator2 actual_e)
+    {
+        using namespace std;
+
+        copy(data_b, data_e, actual_b);
+
+        reverse(exec, actual_b, actual_e);
+
+        bool check = equal(data_b, data_e, reverse_iterator<Iterator2>(actual_e));
+
+        EXPECT_TRUE(check, "wrong result of reverse");
+    }
+
+    template <typename ExecutionPolicy, typename Iterator1, typename Iterator2>
+    typename std::enable_if<is_same_iterator_category<Iterator1, std::forward_iterator_tag>::value>::type
+    operator()(ExecutionPolicy&&, Iterator1, Iterator1, Iterator2, Iterator2)
+    {
+    }
+};
+
+template <typename T>
+void
+test()
+{
+    const std::size_t max_len = 100000;
+
+    Sequence<T> actual(max_len);
+
+    Sequence<T> data(max_len, [](std::size_t i) { return T(i); });
+
+    for (std::size_t len = 0; len < max_len; len = len <= 16 ? len + 1 : std::size_t(3.1415 * len))
+    {
+        invoke_on_all_policies(test_one_policy(), data.begin(), data.begin() + len, actual.begin(),
+                               actual.begin() + len);
+    }
+}
+
+template <typename T>
+struct wrapper
+{
+    T t;
+    wrapper() {}
+    explicit wrapper(T t_) : t(t_) {}
+    bool
+    operator==(const wrapper<T>& a) const
+    {
+        return t == a.t;
+    }
+};
+
+int
+main()
+{
+    test<int32_t>();
+    test<uint16_t>();
+    test<float64_t>();
+#if !defined(_PSTL_ICC_17_TEST_MAC_RELEASE_32_BROKEN)
+    test<wrapper<float64_t>>();
+#endif
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.modifying.operations/alg.reverse/reverse_copy.pass.cpp b/pstl/test/std/algorithms/alg.modifying.operations/alg.reverse/reverse_copy.pass.cpp
new file mode 100644
index 0000000..5334438
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.modifying.operations/alg.reverse/reverse_copy.pass.cpp
@@ -0,0 +1,130 @@
+// -*- C++ -*-
+//===-- reverse_copy.pass.cpp ---------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <iterator>
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+template <typename T>
+struct wrapper
+{
+    T t;
+    wrapper() {}
+    explicit wrapper(T t_) : t(t_) {}
+    wrapper&
+    operator=(const T& t_)
+    {
+        t = t_;
+        return *this;
+    }
+    bool
+    operator==(const wrapper& t_) const
+    {
+        return t == t_.t;
+    }
+};
+
+template <typename T1, typename T2>
+bool
+eq(const wrapper<T1>& a, const wrapper<T2>& b)
+{
+    return a.t == b.t;
+}
+
+template <typename T1, typename T2>
+bool
+eq(const T1& a, const T2& b)
+{
+    return a == b;
+}
+
+// we need to save state here, because we need to test with different types of iterators
+// due to the caller invoke_on_all_policies does forcing modification passed iterator type to cover additional usage cases.
+template <typename Iterator>
+struct test_one_policy
+{
+    Iterator data_b;
+    Iterator data_e;
+    test_one_policy(Iterator b, Iterator e) : data_b(b), data_e(e) {}
+
+#if defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) ||                                                             \
+    defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) // dummy specialization by policy type, in case of broken configuration
+    template <typename Iterator1>
+    typename std::enable_if<is_same_iterator_category<Iterator1, std::random_access_iterator_tag>::value, void>::type
+    operator()(pstl::execution::unsequenced_policy, Iterator1 actual_b, Iterator1 actual_e)
+    {
+    }
+    template <typename Iterator1>
+    typename std::enable_if<is_same_iterator_category<Iterator1, std::random_access_iterator_tag>::value, void>::type
+    operator()(pstl::execution::parallel_unsequenced_policy, Iterator1 actual_b, Iterator1 actual_e)
+    {
+    }
+#endif
+
+    template <typename ExecutionPolicy, typename Iterator1>
+    void
+    operator()(ExecutionPolicy&& exec, Iterator1 actual_b, Iterator1 actual_e)
+    {
+        using namespace std;
+        using T = typename iterator_traits<Iterator1>::value_type;
+
+        fill(actual_b, actual_e, T(-123));
+        Iterator1 actual_return = reverse_copy(exec, data_b, data_e, actual_b);
+
+        EXPECT_TRUE(actual_return == actual_e, "wrong result of reverse_copy");
+
+        const auto n = std::distance(data_b, data_e);
+        Sequence<T> res(n);
+        std::copy(std::reverse_iterator<Iterator>(data_e), std::reverse_iterator<Iterator>(data_b), res.begin());
+
+        EXPECT_EQ_N(res.begin(), actual_b, n, "wrong effect of reverse_copy");
+    }
+};
+
+template <typename T1, typename T2>
+void
+test()
+{
+    typedef typename Sequence<T1>::iterator iterator_type;
+    typedef typename Sequence<T1>::const_bidirectional_iterator cbi_iterator_type;
+
+    const std::size_t max_len = 100000;
+
+    Sequence<T2> actual(max_len);
+
+    Sequence<T1> data(max_len, [](std::size_t i) { return T1(i); });
+
+    for (std::size_t len = 0; len < max_len; len = len <= 16 ? len + 1 : std::size_t(3.1415 * len))
+    {
+        invoke_on_all_policies(test_one_policy<iterator_type>(data.begin(), data.begin() + len), actual.begin(),
+                               actual.begin() + len);
+        invoke_on_all_policies(test_one_policy<cbi_iterator_type>(data.cbibegin(), std::next(data.cbibegin(), len)),
+                               actual.begin(), actual.begin() + len);
+    }
+}
+
+int
+main()
+{
+    test<int16_t, int8_t>();
+    test<uint16_t, float32_t>();
+    test<float64_t, int64_t>();
+    test<wrapper<float64_t>, wrapper<float64_t>>();
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.modifying.operations/copy_move.pass.cpp b/pstl/test/std/algorithms/alg.modifying.operations/copy_move.pass.cpp
new file mode 100644
index 0000000..24b7843
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.modifying.operations/copy_move.pass.cpp
@@ -0,0 +1,197 @@
+// -*- C++ -*-
+//===-- copy_move.pass.cpp ------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+// Tests for copy, move and copy_n
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct run_copy
+{
+
+#if defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) ||                                                             \
+    defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) //dummy specialization by policy type, in case of broken configuration
+    template <typename InputIterator, typename OutputIterator, typename OutputIterator2, typename Size, typename T>
+    void
+    operator()(pstl::execution::unsequenced_policy, InputIterator first, InputIterator last, OutputIterator out_first,
+               OutputIterator out_last, OutputIterator2 expected_first, OutputIterator2 expected_last, Size size,
+               Size n, T trash)
+    {
+    }
+
+    template <typename InputIterator, typename OutputIterator, typename OutputIterator2, typename Size, typename T>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, InputIterator first, InputIterator last,
+               OutputIterator out_first, OutputIterator out_last, OutputIterator2 expected_first,
+               OutputIterator2 expected_last, Size size, Size n, T trash)
+    {
+    }
+#endif
+
+    template <typename Policy, typename InputIterator, typename OutputIterator, typename OutputIterator2, typename Size,
+              typename T>
+    void
+    operator()(Policy&& exec, InputIterator first, InputIterator last, OutputIterator out_first,
+               OutputIterator out_last, OutputIterator2 expected_first, OutputIterator2, Size size, Size n, T trash)
+    {
+        // Cleaning
+        std::fill_n(expected_first, size, trash);
+        std::fill_n(out_first, size, trash);
+
+        // Run copy
+        copy(first, last, expected_first);
+        auto k = copy(exec, first, last, out_first);
+        for (size_t j = 0; j < GuardSize; ++j)
+            ++k;
+        EXPECT_EQ_N(expected_first, out_first, size, "wrong effect from copy");
+        EXPECT_TRUE(out_last == k, "wrong return value from copy");
+
+        // Cleaning
+        std::fill_n(out_first, size, trash);
+        // Run copy_n
+        k = copy_n(exec, first, n, out_first);
+        for (size_t j = 0; j < GuardSize; ++j)
+            ++k;
+        EXPECT_EQ_N(expected_first, out_first, size, "wrong effect from copy_n");
+        EXPECT_TRUE(out_last == k, "wrong return value from copy_n");
+    }
+};
+
+template <typename T>
+struct run_move
+{
+
+#if defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) ||                                                             \
+    defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) //dummy specialization by policy type, in case of broken configuration
+    template <typename InputIterator, typename OutputIterator, typename OutputIterator2, typename Size>
+    void
+    operator()(pstl::execution::unsequenced_policy, InputIterator first, InputIterator last, OutputIterator out_first,
+               OutputIterator out_last, OutputIterator2 expected_first, OutputIterator2 expected_last, Size size,
+               Size n, T trash)
+    {
+    }
+
+    template <typename InputIterator, typename OutputIterator, typename OutputIterator2, typename Size>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, InputIterator first, InputIterator last,
+               OutputIterator out_first, OutputIterator out_last, OutputIterator2 expected_first,
+               OutputIterator2 expected_last, Size size, Size n, T trash)
+    {
+    }
+#endif
+
+    template <typename Policy, typename InputIterator, typename OutputIterator, typename OutputIterator2, typename Size>
+    void
+    operator()(Policy&& exec, InputIterator first, InputIterator last, OutputIterator out_first,
+               OutputIterator out_last, OutputIterator2 expected_first, OutputIterator2, Size size, Size, T trash)
+    {
+        // Cleaning
+        std::fill_n(expected_first, size, trash);
+        std::fill_n(out_first, size, trash);
+
+        // Run move
+        move(first, last, expected_first);
+        auto k = move(exec, first, last, out_first);
+        for (size_t j = 0; j < GuardSize; ++j)
+            ++k;
+        EXPECT_EQ_N(expected_first, out_first, size, "wrong effect from move");
+        EXPECT_TRUE(out_last == k, "wrong return value from move");
+    }
+};
+
+template <typename T>
+struct run_move<Wrapper<T>>
+{
+
+#if defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) ||                                                             \
+    defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) //dummy specialization by policy type, in case of broken configuration
+    template <typename InputIterator, typename OutputIterator, typename OutputIterator2, typename Size>
+    void
+    operator()(pstl::execution::unsequenced_policy, InputIterator first, InputIterator last, OutputIterator out_first,
+               OutputIterator out_last, OutputIterator2 expected_first, OutputIterator2 expected_last, Size size,
+               Size n, Wrapper<T> trash)
+    {
+    }
+
+    template <typename InputIterator, typename OutputIterator, typename OutputIterator2, typename Size>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, InputIterator first, InputIterator last,
+               OutputIterator out_first, OutputIterator out_last, OutputIterator2 expected_first,
+               OutputIterator2 expected_last, Size size, Size n, Wrapper<T> trash)
+    {
+    }
+#endif
+
+    template <typename Policy, typename InputIterator, typename OutputIterator, typename OutputIterator2, typename Size>
+    void
+    operator()(Policy&& exec, InputIterator first, InputIterator last, OutputIterator out_first,
+               OutputIterator out_last, OutputIterator2, OutputIterator2, Size size, Size, Wrapper<T> trash)
+    {
+        // Cleaning
+        std::fill_n(out_first, size, trash);
+        Wrapper<T>::SetMoveCount(0);
+
+        // Run move
+        auto k = move(exec, first, last, out_first);
+        for (size_t j = 0; j < GuardSize; ++j)
+            ++k;
+        EXPECT_TRUE(Wrapper<T>::MoveCount() == size, "wrong effect from move");
+        EXPECT_TRUE(out_last == k, "wrong return value from move");
+    }
+};
+
+template <typename T, typename Convert>
+void
+test(T trash, Convert convert)
+{
+    // Try sequences of various lengths.
+    for (size_t n = 0; n <= 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        // count is number of output elements, plus a handful
+        // more for sake of detecting buffer overruns.
+        Sequence<T> in(n, [&](size_t k) -> T {
+            T val = convert(n ^ k);
+            return val;
+        });
+
+        const size_t outN = n + GuardSize;
+        Sequence<T> out(outN, [=](size_t) { return trash; });
+        Sequence<T> expected(outN, [=](size_t) { return trash; });
+        invoke_on_all_policies(run_copy(), in.begin(), in.end(), out.begin(), out.end(), expected.begin(),
+                               expected.end(), outN, n, trash);
+        invoke_on_all_policies(run_copy(), in.cbegin(), in.cend(), out.begin(), out.end(), expected.begin(),
+                               expected.end(), outN, n, trash);
+        invoke_on_all_policies(run_move<T>(), in.begin(), in.end(), out.begin(), out.end(), expected.begin(),
+                               expected.end(), n, n, trash);
+
+        // For this test const iterator isn't suitable
+        // because const rvalue-reference call copy assignment operator
+    }
+}
+
+int
+main()
+{
+    test<int32_t>(-666, [](size_t j) { return int32_t(j); });
+    test<Wrapper<float64_t>>(Wrapper<float64_t>(-666.0), [](int32_t j) { return Wrapper<float64_t>(j); });
+
+#if !defined(_PSTL_ICC_16_17_TEST_64_TIMEOUT)
+    test<float64_t>(-666.0, [](size_t j) { return float64_t(j); });
+    test<Number>(Number(42, OddTag()), [](int32_t j) { return Number(j, OddTag()); });
+#endif
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.modifying.operations/fill.pass.cpp b/pstl/test/std/algorithms/alg.modifying.operations/fill.pass.cpp
new file mode 100644
index 0000000..d44a1a4
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.modifying.operations/fill.pass.cpp
@@ -0,0 +1,100 @@
+// -*- C++ -*-
+//===-- fill.pass.cpp -----------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct test_fill
+{
+    template <typename It, typename T>
+    bool
+    check(It first, It last, const T& value)
+    {
+        for (; first != last; ++first)
+            if (*first != value)
+                return false;
+        return true;
+    }
+
+    template <typename Policy, typename Iterator, typename T>
+    void
+    operator()(Policy&& exec, Iterator first, Iterator last, const T& value)
+    {
+        fill(first, last, T(value + 1)); // initialize memory with different value
+
+        fill(exec, first, last, value);
+        EXPECT_TRUE(check(first, last, value), "fill wrong result");
+    }
+};
+
+struct test_fill_n
+{
+    template <typename It, typename Size, typename T>
+    bool
+    check(It first, Size n, const T& value)
+    {
+        for (Size i = 0; i < n; ++i, ++first)
+            if (*first != value)
+                return false;
+        return true;
+    }
+
+    template <typename Policy, typename Iterator, typename Size, typename T>
+    void
+    operator()(Policy&& exec, Iterator first, Size n, const T& value)
+    {
+        fill_n(first, n, T(value + 1)); // initialize memory with different value
+
+        const Iterator one_past_last = fill_n(exec, first, n, value);
+        const Iterator expected_return = std::next(first, n);
+
+        EXPECT_TRUE(expected_return == one_past_last, "fill_n should return Iterator to one past the element assigned");
+        EXPECT_TRUE(check(first, n, value), "fill_n wrong result");
+
+        //n == -1
+        const Iterator res = fill_n(exec, first, -1, value);
+        EXPECT_TRUE(res == first, "fill_n wrong result for n == -1");
+    }
+};
+
+template <typename T>
+void
+test_fill_by_type(std::size_t n)
+{
+    Sequence<T> in(n, [](std::size_t) -> T { return T(0); }); //fill with zeros
+    T value = -1;
+
+    invoke_on_all_policies(test_fill(), in.begin(), in.end(), value);
+    invoke_on_all_policies(test_fill_n(), in.begin(), n, value);
+}
+
+int
+main()
+{
+
+    const std::size_t N = 100000;
+
+    for (std::size_t n = 0; n < N; n = n < 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        test_fill_by_type<int32_t>(n);
+        test_fill_by_type<float64_t>(n);
+    }
+
+    std::cout << done() << std::endl;
+
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.modifying.operations/generate.pass.cpp b/pstl/test/std/algorithms/alg.modifying.operations/generate.pass.cpp
new file mode 100644
index 0000000..92d87ea
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.modifying.operations/generate.pass.cpp
@@ -0,0 +1,104 @@
+// -*- C++ -*-
+//===-- generate.pass.cpp -------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <atomic>
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+template <typename T>
+struct Generator_count
+{
+    const T def_val = T(-1);
+    T
+    operator()()
+    {
+        return def_val;
+    }
+    T
+    default_value() const
+    {
+        return def_val;
+    }
+};
+
+struct test_generate
+{
+    template <typename Policy, typename Iterator, typename Size>
+    void
+    operator()(Policy&& exec, Iterator first, Iterator last, Size n)
+    {
+        using namespace std;
+        typedef typename std::iterator_traits<Iterator>::value_type T;
+
+        // Try random-access iterator
+        {
+            Generator_count<T> g;
+            generate(exec, first, last, g);
+            Size count = std::count(first, last, g.default_value());
+            EXPECT_TRUE(count == n, "generate wrong result for generate");
+            std::fill(first, last, T(0));
+        }
+
+        {
+            Generator_count<T> g;
+            const auto m = n / 2;
+            auto actual_last = generate_n(exec, first, m, g);
+            Size count = std::count(first, actual_last, g.default_value());
+            EXPECT_TRUE(count == m && actual_last == std::next(first, m), "generate_n wrong result for generate_n");
+            std::fill(first, actual_last, T(0));
+        }
+    }
+};
+
+template <typename T>
+void
+test_generate_by_type()
+{
+    for (size_t n = 0; n <= 100000; n = n < 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        Sequence<T> in(n, [](size_t) -> T { return T(0); }); //fill by zero
+
+        invoke_on_all_policies(test_generate(), in.begin(), in.end(), in.size());
+    }
+}
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator iter)
+    {
+        auto gen = []() { return T(0); };
+
+        generate(exec, iter, iter, non_const(gen));
+        generate_n(exec, iter, 0, non_const(gen));
+    }
+};
+
+int
+main()
+{
+
+    test_generate_by_type<int32_t>();
+    test_generate_by_type<float64_t>();
+
+    test_algo_basic_single<int32_t>(run_for_rnd_fw<test_non_const<int32_t>>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.modifying.operations/remove.pass.cpp b/pstl/test/std/algorithms/alg.modifying.operations/remove.pass.cpp
new file mode 100644
index 0000000..872b0d2
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.modifying.operations/remove.pass.cpp
@@ -0,0 +1,161 @@
+// -*- C++ -*-
+//===-- remove.pass.cpp ---------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+// Test for remove, remove_if
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct run_remove
+{
+#if defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) ||                                                             \
+    defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) //dummy specialization by policy type, in case of broken configuration
+    template <typename InputIterator, typename OutputIterator, typename Size, typename T>
+    void
+    operator()(pstl::execution::unsequenced_policy, InputIterator first, InputIterator last, OutputIterator out_first,
+               OutputIterator out_last, OutputIterator expected_first, OutputIterator expected_last, Size n,
+               const T& value)
+    {
+    }
+    template <typename InputIterator, typename OutputIterator, typename Size, typename T>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, InputIterator first, InputIterator last,
+               OutputIterator out_first, OutputIterator out_last, OutputIterator expected_first,
+               OutputIterator expected_last, Size n, const T& value)
+    {
+    }
+#endif
+
+    template <typename Policy, typename InputIterator, typename OutputIterator, typename Size, typename T>
+    void
+    operator()(Policy&& exec, InputIterator first, InputIterator last, OutputIterator out_first,
+               OutputIterator out_last, OutputIterator expected_first, OutputIterator expected_last, Size,
+               const T& value)
+    {
+        // Cleaning
+        std::copy(first, last, expected_first);
+        std::copy(first, last, out_first);
+
+        // Run remove
+        OutputIterator i = remove(expected_first, expected_last, value);
+        OutputIterator k = remove(exec, out_first, out_last, value);
+        EXPECT_TRUE(std::distance(expected_first, i) == std::distance(out_first, k), "wrong return value from remove");
+        EXPECT_EQ_N(expected_first, out_first, std::distance(expected_first, i), "wrong remove effect");
+    }
+};
+
+struct run_remove_if
+{
+#if defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) ||                                                             \
+    defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) //dummy specialization by policy type, in case of broken configuration
+    template <typename InputIterator, typename OutputIterator, typename Size, typename Predicate>
+    void
+    operator()(pstl::execution::unsequenced_policy, InputIterator first, InputIterator last, OutputIterator out_first,
+               OutputIterator out_last, OutputIterator expected_first, OutputIterator expected_last, Size n,
+               Predicate pred)
+    {
+    }
+    template <typename InputIterator, typename OutputIterator, typename Size, typename Predicate>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, InputIterator first, InputIterator last,
+               OutputIterator out_first, OutputIterator out_last, OutputIterator expected_first,
+               OutputIterator expected_last, Size n, Predicate pred)
+    {
+    }
+#endif
+
+    template <typename Policy, typename InputIterator, typename OutputIterator, typename Size, typename Predicate>
+    void
+    operator()(Policy&& exec, InputIterator first, InputIterator last, OutputIterator out_first,
+               OutputIterator out_last, OutputIterator expected_first, OutputIterator expected_last, Size,
+               Predicate pred)
+    {
+        // Cleaning
+        std::copy(first, last, expected_first);
+        std::copy(first, last, out_first);
+
+        // Run remove_if
+        OutputIterator i = remove_if(expected_first, expected_last, pred);
+        OutputIterator k = remove_if(exec, out_first, out_last, pred);
+        EXPECT_TRUE(std::distance(expected_first, i) == std::distance(out_first, k),
+                    "wrong return value from remove_if");
+        EXPECT_EQ_N(expected_first, out_first, std::distance(expected_first, i), "wrong remove_if effect");
+    }
+};
+
+template <typename T, typename Predicate, typename Convert>
+void
+test(T trash, const T& value, Predicate pred, Convert convert)
+{
+    const std::size_t max_size = 100000;
+    Sequence<T> out(max_size, [trash](size_t) { return trash; });
+    Sequence<T> expected(max_size, [trash](size_t) { return trash; });
+
+    for (size_t n = 0; n <= max_size; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        Sequence<T> data(n, [&](size_t k) -> T { return convert(k); });
+
+        invoke_on_all_policies(run_remove(), data.begin(), data.end(), out.begin(), out.begin() + n, expected.begin(),
+                               expected.begin() + n, n, value);
+        invoke_on_all_policies(run_remove_if(), data.begin(), data.end(), out.begin(), out.begin() + n,
+                               expected.begin(), expected.begin() + n, n, pred);
+    }
+}
+
+struct test_non_const
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator iter)
+    {
+        auto is_even = [&](float64_t v) {
+            uint32_t i = (uint32_t)v;
+            return i % 2 == 0;
+        };
+
+        invoke_if(exec, [&]() { remove_if(exec, iter, iter, non_const(is_even)); });
+    }
+};
+
+int
+main()
+{
+#if !defined(_PSTL_ICC_18_TEST_EARLY_EXIT_MONOTONIC_RELEASE_BROKEN)
+    test<int32_t>(666, 42, [](int32_t) { return true; }, [](size_t j) { return j; });
+#endif
+
+    test<int32_t>(666, 2001, [](const int32_t& val) { return val != 2001; },
+                  [](size_t j) { return ((j + 1) % 5 & 2) != 0 ? 2001 : -1 - int32_t(j); });
+    test<float64_t>(-666.0, 8.5, [](const float64_t& val) { return val != 8.5; },
+                    [](size_t j) { return ((j + 1) % 7 & 2) != 0 ? 8.5 : float64_t(j % 32 + j); });
+
+#if !defined(_PSTL_ICC_17_TEST_MAC_RELEASE_32_BROKEN)
+    test<Number>(Number(-666, OddTag()), Number(42, OddTag()), IsMultiple(3, OddTag()),
+                 [](int32_t j) { return Number(j, OddTag()); });
+#endif
+
+    test_algo_basic_single<int32_t>(run_for_rnd_fw<test_non_const>());
+
+    test<MemoryChecker>(MemoryChecker{0}, MemoryChecker{1},
+        [](const MemoryChecker& val){ return val.value() == 1; },
+        [](std::size_t idx){ return MemoryChecker{std::int32_t(idx % 3 == 0)}; }
+    );
+    EXPECT_FALSE(MemoryChecker::alive_objects() < 0, "wrong effect from remove,remove_if: number of ctors calls < num of dtors calls");
+    EXPECT_FALSE(MemoryChecker::alive_objects() > 0, "wrong effect from remove,remove_if: number of ctors calls > num of dtors calls");
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.modifying.operations/remove_copy.pass.cpp b/pstl/test/std/algorithms/alg.modifying.operations/remove_copy.pass.cpp
new file mode 100644
index 0000000..9cdd7d6
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.modifying.operations/remove_copy.pass.cpp
@@ -0,0 +1,91 @@
+// -*- C++ -*-
+//===-- remove_copy.pass.cpp ----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct run_remove_copy
+{
+    template <typename Policy, typename InputIterator, typename OutputIterator, typename OutputIterator2, typename Size,
+              typename T>
+    void
+    operator()(Policy&& exec, InputIterator first, InputIterator last, OutputIterator out_first,
+               OutputIterator out_last, OutputIterator2 expected_first, OutputIterator2, Size n, const T& value,
+               T trash)
+    {
+        // Cleaning
+        std::fill_n(expected_first, n, trash);
+        std::fill_n(out_first, n, trash);
+
+        // Run copy_if
+        auto i = std::remove_copy(first, last, expected_first, value);
+        (void)i;
+        auto k = std::remove_copy(exec, first, last, out_first, value);
+        EXPECT_EQ_N(expected_first, out_first, n, "wrong remove_copy effect");
+        for (size_t j = 0; j < GuardSize; ++j)
+        {
+            ++k;
+        }
+        EXPECT_TRUE(out_last == k, "wrong return value from remove_copy");
+    }
+};
+
+template <typename T, typename Convert>
+void
+test(T trash, const T& value, Convert convert, bool check_weakness = true)
+{
+    // Try sequences of various lengths.
+    for (size_t n = 0; n <= 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        // count is number of output elements, plus a handful
+        // more for sake of detecting buffer overruns.
+        size_t count = GuardSize;
+        Sequence<T> in(n, [&](size_t k) -> T {
+            T x = convert(n ^ k);
+            count += !(x == value) ? 1 : 0;
+            return x;
+        });
+        using namespace std;
+
+        Sequence<T> out(count, [=](size_t) { return trash; });
+        Sequence<T> expected(count, [=](size_t) { return trash; });
+        if (check_weakness)
+        {
+            auto expected_result = remove_copy(in.cfbegin(), in.cfend(), expected.begin(), value);
+            size_t m = expected_result - expected.begin();
+            EXPECT_TRUE(n / 4 <= m && m <= 3 * (n + 1) / 4, "weak test for remove_copy");
+        }
+        invoke_on_all_policies(run_remove_copy(), in.begin(), in.end(), out.begin(), out.end(), expected.begin(),
+                               expected.end(), count, value, trash);
+        invoke_on_all_policies(run_remove_copy(), in.cbegin(), in.cend(), out.begin(), out.end(), expected.begin(),
+                               expected.end(), count, value, trash);
+    }
+}
+
+int
+main()
+{
+
+    test<float64_t>(-666.0, 8.5, [](size_t j) { return ((j + 1) % 7 & 2) != 0 ? 8.5 : float64_t(j % 32 + j); });
+
+    test<int32_t>(-666, 42, [](size_t j) { return ((j + 1) % 5 & 2) != 0 ? 42 : -1 - int32_t(j); });
+
+    test<Number>(Number(42, OddTag()), Number(2001, OddTag()),
+                 [](int32_t j) { return ((j + 1) % 3 & 2) != 0 ? Number(2001, OddTag()) : Number(j, OddTag()); });
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.modifying.operations/replace.pass.cpp b/pstl/test/std/algorithms/alg.modifying.operations/replace.pass.cpp
new file mode 100644
index 0000000..9c6ca1ea
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.modifying.operations/replace.pass.cpp
@@ -0,0 +1,160 @@
+// -*- C++ -*-
+//===-- replace.pass.cpp --------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+// This class is needed to check the self-copying
+struct copy_int
+{
+    int32_t value;
+    int32_t copied_times = 0;
+    constexpr explicit copy_int(int32_t val = 0) : value(val) {}
+    constexpr copy_int(copy_int const& other) : value(other.value), copied_times(other.copied_times) { }
+
+    constexpr copy_int&
+    operator=(const copy_int& other)
+    {
+        if (&other == this)
+            copied_times++;
+        else
+        {
+            value = other.value;
+            copied_times = other.copied_times;
+        }
+        return *this;
+    }
+
+    constexpr bool
+    operator==(const copy_int& other) const
+    {
+        return (value == other.value);
+    }
+};
+
+template <typename Iterator>
+struct test_one_policy
+{
+    std::size_t len;
+    Iterator data_b;
+    Iterator data_e;
+    test_one_policy(Iterator data_, std::size_t len_)
+    {
+        len = len_;
+        data_b = data_;
+        data_e = std::next(data_b, len);
+    }
+    template <typename ExecutionPolicy, typename Iterator1, typename Iterator2, typename T, typename Predicate>
+    void
+    operator()(ExecutionPolicy&& exec, Iterator1 expected_b, Iterator1 expected_e, Iterator2 actual_b,
+               Iterator2 actual_e, Predicate pred, const T& value, const T& old_value)
+    {
+        using namespace std;
+
+        copy(data_b, data_e, expected_b);
+        copy(data_b, data_e, actual_b);
+
+        replace(expected_b, expected_e, old_value, value);
+        replace(exec, actual_b, actual_e, old_value, value);
+
+        EXPECT_TRUE((check<T, Iterator2>(actual_b, actual_e)), "wrong result of self assignment check");
+        EXPECT_TRUE(equal(expected_b, expected_e, actual_b), "wrong result of replace");
+
+        copy(data_b, data_e, expected_b);
+        copy(data_b, data_e, actual_b);
+
+        replace_if(expected_b, expected_e, pred, value);
+        replace_if(exec, actual_b, actual_e, pred, value);
+        EXPECT_TRUE(equal(expected_b, expected_e, actual_b), "wrong result of replace_if");
+    }
+
+    template <typename T, typename Iterator1>
+    bool check(Iterator1, Iterator1)
+    {
+        return true;
+    }
+
+    template <typename T, typename Iterator1>
+    typename std::enable_if<std::is_same<T, copy_int>::value, bool>::type_t
+    check(Iterator1 b, Iterator1 e)
+    {
+        return std::all_of(b, e, [](const copy_int& elem) { return elem.copied_times == 0; });
+    }
+};
+
+template <typename T1, typename T2, typename Pred>
+void
+test(Pred pred)
+{
+    typedef typename Sequence<T2>::iterator iterator_type;
+
+    const std::size_t max_len = 100000;
+
+    static constexpr T1 value = T1(0);
+    static constexpr T1 new_value = T1(666);
+
+    Sequence<T2> expected(max_len);
+    Sequence<T2> actual(max_len);
+
+    Sequence<T2> data(max_len, [](std::size_t i) {
+        if (i % 3 == 2)
+        {
+            return T1(i);
+        }
+        else
+        {
+            return value;
+        }
+    });
+
+    for (std::size_t len = 0; len < max_len; len = len <= 16 ? len + 1 : std::size_t(3.1415 * len))
+    {
+        test_one_policy<iterator_type> temp(data.begin(), len);
+
+        invoke_on_all_policies(temp, expected.begin(), expected.begin() + len, actual.begin(), actual.begin() + len,
+                               pred, new_value, value);
+    }
+}
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator iter)
+    {
+        auto is_even = [&](float64_t v) {
+            uint32_t i = (uint32_t)v;
+            return i % 2 == 0;
+        };
+        invoke_if(exec, [&]() { replace_if(exec, iter, iter, non_const(is_even), T(0)); });
+    }
+};
+
+int
+main()
+{
+    test<int32_t, float32_t>(__pstl::__internal::__equal_value<int32_t>(666));
+    test<uint16_t, uint8_t>([](const uint16_t& elem) { return elem % 3 < 2; });
+    test<float64_t, int64_t>([](const float64_t& elem) { return elem * elem - 3.5 * elem > 10; });
+    test<copy_int, copy_int>([](const copy_int& val) { return val.value / 5 > 2; });
+
+    test_algo_basic_single<int32_t>(run_for_rnd_fw<test_non_const<int32_t>>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.modifying.operations/replace_copy.pass.cpp b/pstl/test/std/algorithms/alg.modifying.operations/replace_copy.pass.cpp
new file mode 100644
index 0000000..94d725f
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.modifying.operations/replace_copy.pass.cpp
@@ -0,0 +1,105 @@
+// -*- C++ -*-
+//===-- replace_copy.pass.cpp ---------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+// Tests for replace_copy and replace_copy_if
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct test_replace_copy
+{
+    template <typename Policy, typename InputIterator, typename OutputIterator, typename OutputIterator2, typename Size,
+              typename Predicate, typename T>
+    void
+    operator()(Policy&& exec, InputIterator first, InputIterator last, OutputIterator out_first,
+               OutputIterator out_last, OutputIterator2 expected_first, OutputIterator2, Size n, Predicate pred,
+               const T& old_value, const T& new_value, T trash)
+    {
+        // Cleaning
+        std::fill_n(expected_first, n, trash);
+        std::fill_n(out_first, n, trash);
+        // Run replace_copy
+        auto i = std::replace_copy(first, last, expected_first, old_value, new_value);
+        auto k = std::replace_copy(exec, first, last, out_first, old_value, new_value);
+        EXPECT_EQ_N(expected_first, out_first, n, "wrong replace_copy effect");
+        EXPECT_TRUE(out_last == k, "wrong return value from replace_copy");
+
+        // Cleaning
+        std::fill_n(expected_first, n, trash);
+        std::fill_n(out_first, n, trash);
+        // Run replace_copy_if
+        i = replace_copy_if(first, last, expected_first, pred, new_value);
+        k = replace_copy_if(exec, first, last, out_first, pred, new_value);
+        EXPECT_EQ_N(expected_first, out_first, n, "wrong replace_copy_if effect");
+        EXPECT_TRUE(out_last == k, "wrong return value from replace_copy_if");
+    }
+};
+
+template <typename T, typename Convert, typename Predicate>
+void
+test(T trash, const T& old_value, const T& new_value, Predicate pred, Convert convert)
+{
+    // Try sequences of various lengths.
+    for (size_t n = 0; n <= 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        Sequence<T> in(n, [&](size_t k) -> T { return convert(n ^ k); });
+        Sequence<T> out(n, [=](size_t) { return trash; });
+        Sequence<T> expected(n, [=](size_t) { return trash; });
+
+        invoke_on_all_policies(test_replace_copy(), in.begin(), in.end(), out.begin(), out.end(), expected.begin(),
+                               expected.end(), out.size(), pred, old_value, new_value, trash);
+        invoke_on_all_policies(test_replace_copy(), in.cbegin(), in.cend(), out.begin(), out.end(), expected.begin(),
+                               expected.end(), out.size(), pred, old_value, new_value, trash);
+    }
+}
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename InputIterator, typename OutputInterator>
+    void
+    operator()(Policy&& exec, InputIterator input_iter, OutputInterator out_iter)
+    {
+        auto is_even = [&](float64_t v) {
+            uint32_t i = (uint32_t)v;
+            return i % 2 == 0;
+        };
+
+        invoke_if(exec, [&]() { replace_copy_if(exec, input_iter, input_iter, out_iter, non_const(is_even), T(0)); });
+    }
+};
+
+int
+main()
+{
+
+    test<float64_t>(-666.0, 8.5, 0.33, [](const float64_t& x) { return x * x <= 1024; },
+                    [](size_t j) { return ((j + 1) % 7 & 2) != 0 ? 8.5 : float64_t(j % 32 + j); });
+
+    test<int32_t>(-666, 42, 99, [](const int32_t& x) { return x != 42; },
+                  [](size_t j) { return ((j + 1) % 5 & 2) != 0 ? 42 : -1 - int32_t(j); });
+
+#if !defined(_PSTL_ICC_17_TEST_MAC_RELEASE_32_BROKEN)
+    test<Number>(Number(42, OddTag()), Number(2001, OddTag()), Number(2017, OddTag()), IsMultiple(3, OddTag()),
+                 [](int32_t j) { return ((j + 1) % 3 & 2) != 0 ? Number(2001, OddTag()) : Number(j, OddTag()); });
+#endif
+
+    test_algo_basic_double<int32_t>(run_for_rnd_fw<test_non_const<int32_t>>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.modifying.operations/rotate.pass.cpp b/pstl/test/std/algorithms/alg.modifying.operations/rotate.pass.cpp
new file mode 100644
index 0000000..0d1cfeb
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.modifying.operations/rotate.pass.cpp
@@ -0,0 +1,176 @@
+// -*- C++ -*-
+//===-- rotate.pass.cpp ---------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <iterator>
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+template <typename T>
+struct wrapper
+{
+    T t;
+    int move_count;
+    explicit wrapper(T t_) : t(t_), move_count(0) {}
+    wrapper&
+    operator=(const T& t_)
+    {
+        t = t_;
+        return *this;
+    }
+
+    wrapper(const wrapper<T>& a) : move_count(0) { t = a.t; }
+
+    wrapper<T>&
+    operator=(wrapper<T>& a)
+    {
+        t = a.t;
+        return *this;
+    }
+
+    wrapper<T>&
+    operator=(wrapper<T>&& a)
+    {
+        t = a.t;
+        move_count += 1;
+        return *this;
+    }
+};
+
+template <typename T>
+struct compare
+{
+    bool
+    operator()(const T& a, const T& b)
+    {
+        return a == b;
+    }
+};
+
+template <typename T>
+struct compare<wrapper<T>>
+{
+    bool
+    operator()(const wrapper<T>& a, const wrapper<T>& b)
+    {
+        return a.t == b.t;
+    }
+};
+#include <typeinfo>
+
+struct test_one_policy
+{
+
+#if defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) ||                                                             \
+    defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) // dummy specializations to skip testing in case of broken configuration
+    template <typename Iterator, typename Size>
+    void
+    operator()(pstl::execution::unsequenced_policy, Iterator data_b, Iterator data_e, Iterator actual_b,
+               Iterator actual_e, Size shift)
+    {
+    }
+    template <typename Iterator, typename Size>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, Iterator data_b, Iterator data_e, Iterator actual_b,
+               Iterator actual_e, Size shift)
+    {
+    }
+#endif
+
+    template <typename ExecutionPolicy, typename Iterator, typename Size>
+    void
+    operator()(ExecutionPolicy&& exec, Iterator data_b, Iterator data_e, Iterator actual_b, Iterator actual_e,
+               Size shift)
+    {
+        using namespace std;
+        using T = typename iterator_traits<Iterator>::value_type;
+        Iterator actual_m = std::next(actual_b, shift);
+
+        copy(data_b, data_e, actual_b);
+        Iterator actual_return = rotate(exec, actual_b, actual_m, actual_e);
+
+        EXPECT_TRUE(actual_return == std::next(actual_b, std::distance(actual_m, actual_e)), "wrong result of rotate");
+        auto comparator = compare<T>();
+        bool check = std::equal(actual_return, actual_e, data_b, comparator);
+        check = check && std::equal(actual_b, actual_return, std::next(data_b, shift), comparator);
+
+        EXPECT_TRUE(check, "wrong effect of rotate");
+        EXPECT_TRUE(check_move(exec, actual_b, actual_e, shift), "wrong move test of rotate");
+    }
+
+    template <typename ExecutionPolicy, typename Iterator, typename Size>
+    typename std::enable_if<
+        is_same_iterator_category<Iterator, std::random_access_iterator_tag>::value &&
+            !std::is_same<ExecutionPolicy, std::execution::sequenced_policy>::value &&
+            std::is_same<typename std::iterator_traits<Iterator>::value_type, wrapper<float32_t>>::value,
+        bool>::type
+    check_move(ExecutionPolicy&&, Iterator b, Iterator e, Size shift)
+    {
+        bool result = all_of(b, e, [](wrapper<float32_t>& a) {
+            bool temp = a.move_count > 0;
+            a.move_count = 0;
+            return temp;
+        });
+        return shift == 0 || result;
+    }
+
+    template <typename ExecutionPolicy, typename Iterator, typename Size>
+    typename std::enable_if<
+        !(is_same_iterator_category<Iterator, std::random_access_iterator_tag>::value &&
+          !std::is_same<ExecutionPolicy, std::execution::sequenced_policy>::value &&
+          std::is_same<typename std::iterator_traits<Iterator>::value_type, wrapper<float32_t>>::value),
+        bool>::type
+    check_move(ExecutionPolicy&&, Iterator, Iterator, Size)
+    {
+        return true;
+    }
+};
+
+template <typename T>
+void
+test()
+{
+    const int32_t max_len = 100000;
+
+    Sequence<T> actual(max_len, [](std::size_t i) { return T(i); });
+    Sequence<T> data(max_len, [](std::size_t i) { return T(i); });
+
+    for (int32_t len = 0; len < max_len; len = len <= 16 ? len + 1 : int32_t(3.1415 * len))
+    {
+        int32_t shifts[] = {0, 1, 2, len / 3, (2 * len) / 3, len - 1};
+        for (auto shift : shifts)
+        {
+            if (shift >= 0 && shift < len)
+            {
+                invoke_on_all_policies(test_one_policy(), data.begin(), data.begin() + len, actual.begin(),
+                                       actual.begin() + len, shift);
+            }
+        }
+    }
+}
+
+int
+main()
+{
+    test<int32_t>();
+    test<wrapper<float64_t>>();
+    test<MemoryChecker>();
+    EXPECT_FALSE(MemoryChecker::alive_objects() < 0, "wrong effect from rotate: number of ctors calls < num of dtors calls");
+    EXPECT_FALSE(MemoryChecker::alive_objects() > 0, "wrong effect from rotate: number of ctors calls > num of dtors calls");
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.modifying.operations/rotate_copy.pass.cpp b/pstl/test/std/algorithms/alg.modifying.operations/rotate_copy.pass.cpp
new file mode 100644
index 0000000..539cefc
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.modifying.operations/rotate_copy.pass.cpp
@@ -0,0 +1,146 @@
+// -*- C++ -*-
+//===-- rotate_copy.pass.cpp ----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <iterator>
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+template <typename T>
+struct wrapper;
+
+template <typename T>
+bool
+compare(const wrapper<T>& a, const wrapper<T>& b)
+{
+    return a.t == b.t;
+}
+
+template <typename T>
+bool
+compare(const T& a, const T& b)
+{
+    return a == b;
+}
+
+template <typename T>
+struct wrapper
+{
+    explicit wrapper(T t_) : t(t_) {}
+    wrapper&
+    operator=(const T& t_)
+    {
+        t = t_;
+        return *this;
+    }
+    friend bool
+    compare<T>(const wrapper<T>& a, const wrapper<T>& b);
+
+  private:
+    T t;
+};
+
+template <typename T, typename It1, typename It2>
+struct comparator
+{
+    using T1 = typename std::iterator_traits<It1>::value_type;
+    using T2 = typename std::iterator_traits<It2>::value_type;
+    bool
+    operator()(T1 a, T2 b)
+    {
+        T temp = a;
+        return compare(temp, b);
+    }
+};
+
+struct test_one_policy
+{
+
+#if defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) ||                                                             \
+    defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) // dummy specialization by policy type, in case of broken configuration
+    template <typename Iterator1, typename Iterator2>
+    typename std::enable_if<is_same_iterator_category<Iterator1, std::random_access_iterator_tag>::value, void>::type
+    operator()(pstl::execution::unsequenced_policy, Iterator1 data_b, Iterator1 data_e, Iterator2 actual_b,
+               Iterator2 actual_e, std::size_t shift)
+    {
+    }
+    template <typename Iterator1, typename Iterator2>
+    typename std::enable_if<is_same_iterator_category<Iterator1, std::random_access_iterator_tag>::value, void>::type
+    operator()(pstl::execution::parallel_unsequenced_policy, Iterator1 data_b, Iterator1 data_e, Iterator2 actual_b,
+               Iterator2 actual_e, std::size_t shift)
+    {
+    }
+#endif
+
+    template <typename ExecutionPolicy, typename Iterator1, typename Iterator2>
+    void
+    operator()(ExecutionPolicy&& exec, Iterator1 data_b, Iterator1 data_e, Iterator2 actual_b, Iterator2 actual_e,
+               std::size_t shift)
+    {
+        using namespace std;
+        using T = typename iterator_traits<Iterator2>::value_type;
+        Iterator1 data_m = std::next(data_b, shift);
+
+        fill(actual_b, actual_e, T(-123));
+        Iterator2 actual_return = rotate_copy(exec, data_b, data_m, data_e, actual_b);
+
+        EXPECT_TRUE(actual_return == actual_e, "wrong result of rotate_copy");
+        auto comparer = comparator<T, Iterator1, Iterator2>();
+        bool check = std::equal(data_m, data_e, actual_b, comparer);
+        check = check && std::equal(data_b, data_m, std::next(actual_b, std::distance(data_m, data_e)), comparer);
+
+        EXPECT_TRUE(check, "wrong effect of rotate_copy");
+    }
+};
+
+template <typename T1, typename T2>
+void
+test()
+{
+
+    const std::size_t max_len = 100000;
+
+    Sequence<T2> actual(max_len, [](std::size_t i) { return T1(i); });
+
+    Sequence<T1> data(max_len, [](std::size_t i) { return T1(i); });
+
+    for (std::size_t len = 0; len < max_len; len = len <= 16 ? len + 1 : std::size_t(3.1415 * len))
+    {
+        std::size_t shifts[] = {0, 1, 2, len / 3, (2 * len) / 3, len - 1};
+        for (std::size_t shift : shifts)
+        {
+            if (shift > 0 && shift < len)
+            {
+                invoke_on_all_policies(test_one_policy(), data.begin(), data.begin() + len, actual.begin(),
+                                       actual.begin() + len, shift);
+                invoke_on_all_policies(test_one_policy(), data.cbegin(), data.cbegin() + len, actual.begin(),
+                                       actual.begin() + len, shift);
+            }
+        }
+    }
+}
+
+int
+main()
+{
+    test<int32_t, int8_t>();
+    test<uint16_t, float32_t>();
+    test<float64_t, int64_t>();
+    test<wrapper<float64_t>, wrapper<float64_t>>();
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.modifying.operations/swap_ranges.pass.cpp b/pstl/test/std/algorithms/alg.modifying.operations/swap_ranges.pass.cpp
new file mode 100644
index 0000000..c3c3693
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.modifying.operations/swap_ranges.pass.cpp
@@ -0,0 +1,133 @@
+// -*- C++ -*-
+//===-- swap_ranges.pass.cpp ----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <iterator>
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+template <typename T>
+struct wrapper
+{
+    T t;
+    std::size_t number_of_swaps = 0;
+    wrapper() {}
+    explicit wrapper(T t_) : t(t_) {}
+    template <typename U>
+    void
+    operator=(const U& b)
+    {
+        t = b;
+    }
+    bool
+    operator==(const wrapper<T>& a) const
+    {
+        return t == a.t;
+    }
+};
+
+template <typename T>
+void
+swap(wrapper<T>& a, wrapper<T>& b)
+{
+    std::swap(a.t, b.t);
+    a.number_of_swaps++;
+    b.number_of_swaps++;
+}
+
+template <typename T>
+struct check_swap
+{
+    bool
+    operator()(T&)
+    {
+        return true;
+    }
+};
+
+template <typename T>
+struct check_swap<wrapper<T>>
+{
+    bool
+    operator()(wrapper<T>& a)
+    {
+        bool temp = (a.number_of_swaps == 1);
+        a.number_of_swaps = 0;
+        return temp;
+    }
+};
+
+struct test_one_policy
+{
+    template <typename ExecutionPolicy, typename Iterator1, typename Iterator2>
+    void
+    operator()(ExecutionPolicy&& exec, Iterator1 data_b, Iterator1 data_e, Iterator2 actual_b, Iterator2 actual_e)
+    {
+        using namespace std;
+        using T_ref = typename iterator_traits<Iterator1>::reference;
+        using T = typename iterator_traits<Iterator1>::value_type;
+
+        iota(data_b, data_e, 0);
+        iota(actual_b, actual_e, std::distance(data_b, data_e));
+
+        Iterator2 actual_return = swap_ranges(exec, data_b, data_e, actual_b);
+        bool check_return = (actual_return == actual_e);
+        EXPECT_TRUE(check_return, "wrong result of swap_ranges");
+        if (check_return)
+        {
+            std::size_t i = 0;
+            bool check = all_of(actual_b, actual_e, [&i](T_ref a) { return a == T(i++); }) &&
+                         all_of(data_b, data_e, [&i](T_ref a) { return a == T(i++); });
+
+            EXPECT_TRUE(check, "wrong effect of swap_ranges");
+
+            if (check)
+            {
+                bool swap_check =
+                    all_of(data_b, data_e, check_swap<T>()) && all_of(actual_b, actual_e, check_swap<T>());
+                EXPECT_TRUE(swap_check, "wrong effect of swap_ranges swap check");
+            }
+        }
+    }
+};
+
+template <typename T>
+void
+test()
+{
+    const std::size_t max_len = 100000;
+
+    Sequence<T> data(max_len);
+    Sequence<T> actual(max_len);
+
+    for (std::size_t len = 0; len < max_len; len = len <= 16 ? len + 1 : std::size_t(3.1415 * len))
+    {
+        invoke_on_all_policies(test_one_policy(), data.begin(), data.begin() + len, actual.begin(),
+                               actual.begin() + len);
+    }
+}
+
+int
+main()
+{
+    test<wrapper<uint16_t>>();
+    test<wrapper<float64_t>>();
+    test<int32_t>();
+    test<float32_t>();
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.modifying.operations/transform_binary.pass.cpp b/pstl/test/std/algorithms/alg.modifying.operations/transform_binary.pass.cpp
new file mode 100644
index 0000000..949e6f5
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.modifying.operations/transform_binary.pass.cpp
@@ -0,0 +1,122 @@
+// -*- C++ -*-
+//===-- transform_binary.pass.cpp -----------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+template <typename In1, typename In2, typename Out>
+class TheOperation
+{
+    Out val;
+
+  public:
+    TheOperation(Out v) : val(v) {}
+    Out
+    operator()(const In1& x, const In2& y) const
+    {
+        return Out(val + x - y);
+    }
+};
+
+template <typename InputIterator1, typename InputIterator2, typename OutputIterator>
+void
+check_and_reset(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, OutputIterator out_first)
+{
+    typedef typename std::iterator_traits<OutputIterator>::value_type Out;
+    typename std::iterator_traits<OutputIterator>::difference_type k = 0;
+    for (; first1 != last1; ++first1, ++first2, ++out_first, ++k)
+    {
+        // check
+        Out expected = Out(1.5) + *first1 - *first2;
+        Out actual = *out_first;
+        if (std::is_floating_point<Out>::value)
+        {
+            EXPECT_TRUE((expected > actual ? expected - actual : actual - expected) < 1e7,
+                        "wrong value in output sequence");
+        }
+        else
+        {
+            EXPECT_EQ(expected, actual, "wrong value in output sequence");
+        }
+        // reset
+        *out_first = k % 7 != 4 ? 7 * k - 5 : 0;
+    }
+}
+
+struct test_one_policy
+{
+    template <typename Policy, typename InputIterator1, typename InputIterator2, typename OutputIterator,
+              typename BinaryOp>
+    void
+    operator()(Policy&& exec, InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2,
+               OutputIterator out_first, OutputIterator, BinaryOp op)
+    {
+        auto result = std::transform(exec, first1, last1, first2, out_first, op);
+        (void)result;
+        check_and_reset(first1, last1, first2, out_first);
+    }
+};
+
+template <typename In1, typename In2, typename Out, typename Predicate>
+void
+test(Predicate pred)
+{
+    for (size_t n = 0; n <= 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        Sequence<In1> in1(n, [](size_t k) { return k % 5 != 1 ? 3 * k - 7 : 0; });
+        Sequence<In2> in2(n, [](size_t k) { return k % 7 != 2 ? 5 * k - 5 : 0; });
+
+        Sequence<Out> out(n, [](size_t) { return -1; });
+
+        invoke_on_all_policies(test_one_policy(), in1.begin(), in1.end(), in2.begin(), in2.end(), out.begin(),
+                               out.end(), pred);
+        invoke_on_all_policies(test_one_policy(), in1.cbegin(), in1.cend(), in2.cbegin(), in2.cend(), out.begin(),
+                               out.end(), pred);
+    }
+}
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename InputIterator, typename OutputInterator>
+    void
+    operator()(Policy&& exec, InputIterator input_iter, OutputInterator out_iter)
+    {
+        invoke_if(exec, [&]() {
+            InputIterator input_iter2 = input_iter;
+            transform(exec, input_iter, input_iter, input_iter2, out_iter, non_const(std::plus<T>()));
+        });
+    }
+};
+
+int
+main()
+{
+    //const operator()
+    test<int32_t, int32_t, int32_t>(TheOperation<int32_t, int32_t, int32_t>(1));
+    test<float32_t, float32_t, float32_t>(TheOperation<float32_t, float32_t, float32_t>(1.5));
+    //non-const operator()
+    test<int32_t, float32_t, float32_t>(non_const(TheOperation<int32_t, float32_t, float32_t>(1.5)));
+    test<int64_t, float64_t, float32_t>(non_const(TheOperation<int64_t, float64_t, float32_t>(1.5)));
+    //lambda
+    test<int8_t, float64_t, int8_t>([](const int8_t& x, const float64_t& y) { return int8_t(int8_t(1.5) + x - y); });
+
+    test_algo_basic_double<int32_t>(run_for_rnd_fw<test_non_const<int32_t>>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.modifying.operations/transform_unary.pass.cpp b/pstl/test/std/algorithms/alg.modifying.operations/transform_unary.pass.cpp
new file mode 100644
index 0000000..69a410c
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.modifying.operations/transform_unary.pass.cpp
@@ -0,0 +1,91 @@
+// -*- C++ -*-
+//===-- transform_unary.pass.cpp ------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+template <typename InputIterator, typename OutputIterator>
+void
+check_and_reset(InputIterator first, InputIterator last, OutputIterator out_first)
+{
+    typedef typename std::iterator_traits<OutputIterator>::value_type Out;
+    typename std::iterator_traits<OutputIterator>::difference_type k = 0;
+    for (; first != last; ++first, ++out_first, ++k)
+    {
+        // check
+        Out expected = 1 - *first;
+        Out actual = *out_first;
+        EXPECT_EQ(expected, actual, "wrong value in output sequence");
+        // reset
+        *out_first = k % 7 != 4 ? 7 * k - 5 : 0;
+    }
+}
+
+struct test_one_policy
+{
+    template <typename Policy, typename InputIterator, typename OutputIterator, typename UnaryOp>
+    void
+    operator()(Policy&& exec, InputIterator first, InputIterator last, OutputIterator out_first,
+               OutputIterator out_last, UnaryOp op)
+    {
+        auto orr = std::transform(exec, first, last, out_first, op);
+        EXPECT_TRUE(out_last == orr, "transform returned wrong iterator");
+        check_and_reset(first, last, out_first);
+    }
+};
+
+template <typename Tin, typename Tout>
+void
+test()
+{
+    for (size_t n = 0; n <= 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        Sequence<Tin> in(n, [](int32_t k) { return k % 5 != 1 ? 3 * k - 7 : 0; });
+
+        Sequence<Tout> out(n);
+
+        const auto flip = Complement<Tin, Tout>(1);
+        invoke_on_all_policies(test_one_policy(), in.begin(), in.end(), out.begin(), out.end(), flip);
+        invoke_on_all_policies(test_one_policy(), in.cbegin(), in.cend(), out.begin(), out.end(), flip);
+    }
+}
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename InputIterator, typename OutputInterator>
+    void
+    operator()(Policy&& exec, InputIterator input_iter, OutputInterator out_iter)
+    {
+        invoke_if(exec, [&]() { transform(exec, input_iter, input_iter, out_iter, non_const(std::negate<T>())); });
+    }
+};
+
+int
+main()
+{
+    test<int32_t, int32_t>();
+    test<int32_t, float32_t>();
+    test<uint16_t, float32_t>();
+    test<float32_t, float64_t>();
+    test<float64_t, float64_t>();
+
+    test_algo_basic_double<int32_t>(run_for_rnd_fw<test_non_const<int32_t>>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.modifying.operations/unique.pass.cpp b/pstl/test/std/algorithms/alg.modifying.operations/unique.pass.cpp
new file mode 100644
index 0000000..fbd4742
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.modifying.operations/unique.pass.cpp
@@ -0,0 +1,163 @@
+// -*- C++ -*-
+//===-- unique.pass.cpp ---------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+// Test for unique
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct run_unique
+{
+#if defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) ||                                                             \
+    defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) //dummy specialization by policy type, in case of broken configuration
+    template <typename ForwardIt, typename Generator>
+    void
+    operator()(pstl::execution::unsequenced_policy, ForwardIt first1, ForwardIt last1, ForwardIt first2,
+               ForwardIt last2, Generator generator)
+    {
+    }
+
+    template <typename ForwardIt, typename Generator>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, ForwardIt first1, ForwardIt last1, ForwardIt first2,
+               ForwardIt last2, Generator generator)
+    {
+    }
+
+    template <typename ForwardIt, typename BinaryPred, typename Generator>
+    void
+    operator()(pstl::execution::unsequenced_policy, ForwardIt first1, ForwardIt last1, ForwardIt first2,
+               ForwardIt last2, BinaryPred pred, Generator generator)
+    {
+    }
+
+    template <typename ForwardIt, typename BinaryPred, typename Generator>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, ForwardIt first1, ForwardIt last1, ForwardIt first2,
+               ForwardIt last2, BinaryPred pred, Generator generator)
+    {
+    }
+#endif
+
+    template <typename Policy, typename ForwardIt, typename Generator>
+    void
+    operator()(Policy&& exec, ForwardIt first1, ForwardIt last1, ForwardIt first2, ForwardIt last2, Generator generator)
+    {
+        using namespace std;
+
+        // Preparation
+        fill_data(first1, last1, generator);
+        fill_data(first2, last2, generator);
+
+        ForwardIt i = unique(first1, last1);
+        ForwardIt k = unique(exec, first2, last2);
+
+        auto n = std::distance(first1, i);
+        EXPECT_TRUE(std::distance(first2, k) == n, "wrong return value from unique without predicate");
+        EXPECT_EQ_N(first1, first2, n, "wrong effect from unique without predicate");
+    }
+
+    template <typename Policy, typename ForwardIt, typename BinaryPred, typename Generator>
+    void
+    operator()(Policy&& exec, ForwardIt first1, ForwardIt last1, ForwardIt first2, ForwardIt last2, BinaryPred pred,
+               Generator generator)
+    {
+        using namespace std;
+
+        // Preparation
+        fill_data(first1, last1, generator);
+        fill_data(first2, last2, generator);
+
+        ForwardIt i = unique(first1, last1, pred);
+        ForwardIt k = unique(exec, first2, last2, pred);
+
+        auto n = std::distance(first1, i);
+        EXPECT_TRUE(std::distance(first2, k) == n, "wrong return value from unique with predicate");
+        EXPECT_EQ_N(first1, first2, n, "wrong effect from unique with predicate");
+    }
+};
+
+template <typename T, typename Generator, typename Predicate>
+void
+test(Generator generator, Predicate pred)
+{
+    const std::size_t max_size = 1000000;
+    Sequence<T> in(max_size, [](size_t v) { return T(v); });
+    Sequence<T> exp(max_size, [](size_t v) { return T(v); });
+
+    for (size_t n = 0; n <= max_size; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        invoke_on_all_policies(run_unique(), exp.begin(), exp.begin() + n, in.begin(), in.begin() + n, generator);
+        invoke_on_all_policies(run_unique(), exp.begin(), exp.begin() + n, in.begin(), in.begin() + n, pred, generator);
+    }
+}
+
+template <typename T>
+struct LocalWrapper
+{
+    T my_val;
+
+    explicit LocalWrapper(T k) : my_val(k) {}
+    LocalWrapper(LocalWrapper&& input) : my_val(std::move(input.my_val)) {}
+    LocalWrapper&
+    operator=(LocalWrapper&& input)
+    {
+        my_val = std::move(input.my_val);
+        return *this;
+    }
+    friend bool
+    operator==(const LocalWrapper<T>& x, const LocalWrapper<T>& y)
+    {
+        return x.my_val == y.my_val;
+    }
+};
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator iter)
+    {
+        invoke_if(exec, [&]() { unique(exec, iter, iter, non_const(std::equal_to<T>())); });
+    }
+};
+
+int
+main()
+{
+#if !defined(_PSTL_ICC_16_17_18_TEST_UNIQUE_MASK_RELEASE_BROKEN)
+    test<int32_t>([](size_t j) { return j / 3; },
+                  [](const int32_t& val1, const int32_t& val2) { return val1 * val1 == val2 * val2; });
+    test<float64_t>([](size_t) { return float64_t(1); },
+                    [](const float64_t& val1, const float64_t& val2) { return val1 != val2; });
+#endif
+    test<LocalWrapper<uint32_t>>([](size_t j) { return LocalWrapper<uint32_t>(j); },
+                                 [](const LocalWrapper<uint32_t>& val1, const LocalWrapper<uint32_t>& val2) {
+                                     return val1.my_val != val2.my_val;
+                                 });
+
+    test_algo_basic_single<int32_t>(run_for_rnd_fw<test_non_const<int32_t>>());
+
+    test<MemoryChecker>(
+        [](std::size_t idx){ return MemoryChecker{std::int32_t(idx / 3)}; },
+        [](const MemoryChecker& val1, const MemoryChecker& val2){ return val1.value() == val2.value(); });
+    EXPECT_FALSE(MemoryChecker::alive_objects() < 0, "wrong effect from unique: number of ctors calls < num of dtors calls");
+    EXPECT_FALSE(MemoryChecker::alive_objects() > 0, "wrong effect from unique: number of ctors calls > num of dtors calls");
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.modifying.operations/unique_copy_equal.pass.cpp b/pstl/test/std/algorithms/alg.modifying.operations/unique_copy_equal.pass.cpp
new file mode 100644
index 0000000..356d4d2
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.modifying.operations/unique_copy_equal.pass.cpp
@@ -0,0 +1,135 @@
+// -*- C++ -*-
+//===-- unique_copy_equal.pass.cpp ----------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+// Tests for unique_copy
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct run_unique_copy
+{
+#if defined(_PSTL_ICC_16_VC14_TEST_PAR_TBB_RT_RELEASE_64_BROKEN) // dummy specializations to skip testing in case of broken configuration
+    template <typename InputIterator, typename OutputIterator, typename OutputIterator2, typename Size,
+              typename Predicate, typename T>
+    void
+    operator()(pstl::execution::parallel_policy, InputIterator first, InputIterator last, OutputIterator out_first,
+               OutputIterator out_last, OutputIterator2 expected_first, OutputIterator2 expected_last, Size n,
+               Predicate pred, T trash)
+    {
+    }
+
+    template <typename InputIterator, typename OutputIterator, typename OutputIterator2, typename Size,
+              typename Predicate, typename T>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, InputIterator first, InputIterator last,
+               OutputIterator out_first, OutputIterator out_last, OutputIterator2 expected_first,
+               OutputIterator2 expected_last, Size n, Predicate pred, T trash)
+    {
+    }
+#endif
+
+    template <typename Policy, typename InputIterator, typename OutputIterator, typename OutputIterator2, typename Size,
+              typename Predicate, typename T>
+    void
+    operator()(Policy&& exec, InputIterator first, InputIterator last, OutputIterator out_first,
+               OutputIterator out_last, OutputIterator2 expected_first, OutputIterator2, Size n, Predicate pred,
+               T trash)
+    {
+        // Cleaning
+        std::fill_n(expected_first, n, trash);
+        std::fill_n(out_first, n, trash);
+
+        // Run unique_copy
+        auto i = unique_copy(first, last, expected_first);
+        auto k = unique_copy(exec, first, last, out_first);
+        EXPECT_EQ_N(expected_first, out_first, n, "wrong unique_copy effect");
+        for (size_t j = 0; j < GuardSize; ++j)
+        {
+            ++k;
+        }
+        EXPECT_TRUE(out_last == k, "wrong return value from unique_copy");
+
+        // Cleaning
+        std::fill_n(expected_first, n, trash);
+        std::fill_n(out_first, n, trash);
+        // Run unique_copy with predicate
+        i = unique_copy(first, last, expected_first, pred);
+        k = unique_copy(exec, first, last, out_first, pred);
+        EXPECT_EQ_N(expected_first, out_first, n, "wrong unique_copy with predicate effect");
+        for (size_t j = 0; j < GuardSize; ++j)
+        {
+            ++k;
+        }
+        EXPECT_TRUE(out_last == k, "wrong return value from unique_copy with predicate");
+    }
+};
+
+template <typename T, typename BinaryPredicate, typename Convert>
+void
+test(T trash, BinaryPredicate pred, Convert convert, bool check_weakness = true)
+{
+    // Try sequences of various lengths.
+    for (size_t n = 0; n <= 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        // count is number of output elements, plus a handful
+        // more for sake of detecting buffer overruns.
+        Sequence<T> in(n, [&](size_t k) -> T { return convert(k ^ n); });
+        using namespace std;
+        size_t count = GuardSize;
+        for (size_t k = 0; k < in.size(); ++k)
+            count += k == 0 || !pred(in[k], in[k - 1]) ? 1 : 0;
+        Sequence<T> out(count, [=](size_t) { return trash; });
+        Sequence<T> expected(count, [=](size_t) { return trash; });
+        if (check_weakness)
+        {
+            auto expected_result = unique_copy(in.begin(), in.end(), expected.begin(), pred);
+            size_t m = expected_result - expected.begin();
+            EXPECT_TRUE(n / (n < 10000 ? 4 : 6) <= m && m <= (3 * n + 1) / 4, "weak test for unique_copy");
+        }
+        invoke_on_all_policies(run_unique_copy(), in.begin(), in.end(), out.begin(), out.end(), expected.begin(),
+                               expected.end(), count, pred, trash);
+    }
+}
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename InputIterator, typename OutputInterator>
+    void
+    operator()(Policy&& exec, InputIterator input_iter, OutputInterator out_iter)
+    {
+        unique_copy(exec, input_iter, input_iter, out_iter, non_const(std::equal_to<T>()));
+    }
+};
+
+int
+main()
+{
+    test<Number>(Number(42, OddTag()), std::equal_to<Number>(),
+                 [](int32_t j) { return Number(3 * j / 13 ^ (j & 8), OddTag()); });
+
+    test<float32_t>(float32_t(42), std::equal_to<float32_t>(),
+                    [](int32_t j) { return float32_t(5 * j / 23 ^ (j / 7)); });
+#if !defined(_PSTL_ICC_16_17_TEST_REDUCTION_RELEASE_BROKEN)
+    test<float32_t>(float32_t(42), [](float32_t, float32_t) { return false; }, [](int32_t j) { return float32_t(j); },
+                    false);
+#endif
+
+    test_algo_basic_double<int32_t>(run_for_rnd_fw<test_non_const<int32_t>>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.nonmodifying/adjacent_find.pass.cpp b/pstl/test/std/algorithms/alg.nonmodifying/adjacent_find.pass.cpp
new file mode 100644
index 0000000..36a623b
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.nonmodifying/adjacent_find.pass.cpp
@@ -0,0 +1,114 @@
+// -*- C++ -*-
+//===-- adjacent_find.pass.cpp --------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct test_adjacent_find
+{
+    template <typename Policy, typename Iterator, typename Pred>
+    void
+    operator()(Policy&& exec, Iterator first, Iterator last, Pred pred)
+    {
+        using namespace std;
+
+        auto k = std::adjacent_find(first, last, pred);
+        auto i = adjacent_find(exec, first, last, pred);
+        EXPECT_TRUE(i == k, "wrong return value from adjacent_find with predicate");
+
+        i = adjacent_find(exec, first, last);
+        EXPECT_TRUE(i == k, "wrong return value from adjacent_find without predicate");
+    }
+};
+
+template <typename T>
+void
+test_adjacent_find_by_type()
+{
+
+    size_t counts[] = {2, 3, 500};
+    for (size_t c = 0; c < const_size(counts); ++c)
+    {
+
+        for (size_t e = 0; e < (counts[c] >= 64 ? 64 : (counts[c] == 2 ? 1 : 2)); ++e)
+        {
+            Sequence<T> in(counts[c], [](size_t v) -> T { return T(v); }); //fill 0...n
+            in[e] = in[e + 1] = -1;                                        //make an adjacent pair
+
+            auto i = std::adjacent_find(in.cbegin(), in.cend(), std::equal_to<T>());
+            EXPECT_TRUE(i == in.cbegin() + e, "std::adjacent_find returned wrong result");
+
+            invoke_on_all_policies(test_adjacent_find(), in.begin(), in.end(), std::equal_to<T>());
+            invoke_on_all_policies(test_adjacent_find(), in.cbegin(), in.cend(), std::equal_to<T>());
+        }
+    }
+
+    //special cases: size=0, size=1;
+    for (size_t expect = 0; expect < 1; ++expect)
+    {
+        Sequence<T> in(expect, [](size_t v) -> T { return T(v); }); //fill 0...n
+        auto i = std::adjacent_find(in.cbegin(), in.cend(), std::equal_to<T>());
+        EXPECT_TRUE(i == in.cbegin() + expect, "std::adjacent_find returned wrong result");
+
+        invoke_on_all_policies(test_adjacent_find(), in.begin(), in.end(), std::equal_to<T>());
+        invoke_on_all_policies(test_adjacent_find(), in.cbegin(), in.cend(), std::equal_to<T>());
+    }
+
+    //special cases:
+    Sequence<T> a1 = {5, 5, 5, 6, 7, 8, 9};
+    invoke_on_all_policies(test_adjacent_find(), a1.begin(), a1.end(), std::equal_to<T>());
+    invoke_on_all_policies(test_adjacent_find(), a1.begin() + 1, a1.end(), std::equal_to<T>());
+
+    invoke_on_all_policies(test_adjacent_find(), a1.cbegin(), a1.cend(), std::equal_to<T>());
+    invoke_on_all_policies(test_adjacent_find(), a1.cbegin() + 1, a1.cend(), std::equal_to<T>());
+
+    Sequence<T> a2 = {5, 6, 7, 8, 9, 9};
+    invoke_on_all_policies(test_adjacent_find(), a2.begin(), a2.end(), std::equal_to<T>());
+    invoke_on_all_policies(test_adjacent_find(), a2.begin(), a2.end() - 1, std::equal_to<T>());
+
+    invoke_on_all_policies(test_adjacent_find(), a2.cbegin(), a2.cend(), std::equal_to<T>());
+    invoke_on_all_policies(test_adjacent_find(), a2.cbegin(), a2.cend() - 1, std::equal_to<T>());
+
+    Sequence<T> a3 = {5, 6, 6, 6, 7, 9, 9, 9, 9};
+    invoke_on_all_policies(test_adjacent_find(), a3.begin(), a3.end(), std::equal_to<T>());
+
+    invoke_on_all_policies(test_adjacent_find(), a3.cbegin(), a3.cend(), std::equal_to<T>());
+}
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator iter)
+    {
+        adjacent_find(exec, iter, iter, non_const(std::equal_to<T>()));
+    }
+};
+
+int
+main()
+{
+
+    test_adjacent_find_by_type<int32_t>();
+    test_adjacent_find_by_type<float64_t>();
+
+    test_algo_basic_single<int32_t>(run_for_rnd_bi<test_non_const<int32_t>>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.nonmodifying/all_of.pass.cpp b/pstl/test/std/algorithms/alg.nonmodifying/all_of.pass.cpp
new file mode 100644
index 0000000..ec23dc4
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.nonmodifying/all_of.pass.cpp
@@ -0,0 +1,117 @@
+// -*- C++ -*-
+//===-- all_of.pass.cpp ---------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+/*
+  TODO: consider implementing the following tests for a better code coverage
+  - correctness
+  - bad input argument (if applicable)
+  - data corruption around/of input and output
+  - correctly work with nested parallelism
+  - check that algorithm does not require anything more than is described in its requirements section
+*/
+
+using namespace TestUtils;
+
+struct test_all_of
+{
+    template <typename ExecutionPolicy, typename Iterator, typename Predicate>
+    void
+    operator()(ExecutionPolicy&& exec, Iterator begin, Iterator end, Predicate pred, bool expected)
+    {
+
+        auto actualr = std::all_of(exec, begin, end, pred);
+        EXPECT_EQ(expected, actualr, "result for all_of");
+    }
+};
+
+template <typename T>
+struct Parity
+{
+    bool parity;
+
+  public:
+    Parity(bool parity_) : parity(parity_) {}
+    bool
+    operator()(T value) const
+    {
+        return (size_t(value) ^ parity) % 2 == 0;
+    }
+};
+
+template <typename T>
+void
+test(size_t bits)
+{
+    for (size_t n = 0; n <= 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+
+        // Sequence of odd values
+        Sequence<T> in(n, [n, bits](size_t) { return T(2 * HashBits(n, bits - 1) ^ 1); });
+
+        // Even value, or false when T is bool.
+        T spike(2 * HashBits(n, bits - 1));
+        Sequence<T> inCopy(in);
+
+        invoke_on_all_policies(test_all_of(), in.begin(), in.end(), Parity<T>(1), true);
+        invoke_on_all_policies(test_all_of(), in.cbegin(), in.cend(), Parity<T>(1), true);
+        EXPECT_EQ(in, inCopy, "all_of modified input sequence");
+        if (n > 0)
+        {
+            // Sprinkle in a miss
+            in[2 * n / 3] = spike;
+            invoke_on_all_policies(test_all_of(), in.begin(), in.end(), Parity<T>(1), false);
+            invoke_on_all_policies(test_all_of(), in.cbegin(), in.cend(), Parity<T>(1), false);
+
+            // Sprinkle in a few more misses
+            in[n / 2] = spike;
+            in[n / 3] = spike;
+            invoke_on_all_policies(test_all_of(), in.begin(), in.end(), Parity<T>(1), false);
+            invoke_on_all_policies(test_all_of(), in.cbegin(), in.cend(), Parity<T>(1), false);
+        }
+    }
+}
+
+struct test_non_const
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator iter)
+    {
+        auto is_even = [&](float64_t v) {
+            uint32_t i = (uint32_t)v;
+            return i % 2 == 0;
+        };
+        all_of(exec, iter, iter, non_const(is_even));
+    }
+};
+
+int
+main()
+{
+    test<int32_t>(8 * sizeof(int32_t));
+    test<uint16_t>(8 * sizeof(uint16_t));
+    test<float64_t>(53);
+#if !defined(_PSTL_ICC_16_17_TEST_REDUCTION_BOOL_TYPE_RELEASE_64_BROKEN)
+    test<bool>(1);
+#endif
+
+    test_algo_basic_single<int32_t>(run_for_rnd_fw<test_non_const>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.nonmodifying/any_of.pass.cpp b/pstl/test/std/algorithms/alg.nonmodifying/any_of.pass.cpp
new file mode 100644
index 0000000..97d1691
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.nonmodifying/any_of.pass.cpp
@@ -0,0 +1,103 @@
+// -*- C++ -*-
+//===-- any_of.pass.cpp ---------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+/*
+  TODO: consider implementing the following tests for a better code coverage
+  - correctness
+  - bad input argument (if applicable)
+  - data corruption around/of input and output
+  - correctly work with nested parallelism
+  - check that algorithm does not require anything more than is described in its requirements section
+*/
+
+using namespace TestUtils;
+
+struct test_any_of
+{
+    template <typename ExecutionPolicy, typename Iterator, typename Predicate>
+    void
+    operator()(ExecutionPolicy&& exec, Iterator begin, Iterator end, Predicate pred, bool expected)
+    {
+
+        auto actualr = std::any_of(exec, begin, end, pred);
+        EXPECT_EQ(expected, actualr, "result for any_of");
+    }
+};
+
+template <typename T>
+void
+test(size_t bits)
+{
+    for (size_t n = 0; n <= 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+
+        // Sequence of odd values
+        Sequence<T> in(n, [n, bits](size_t) { return T(2 * HashBits(n, bits - 1) ^ 1); });
+
+        // Even value, or false when T is bool.
+        T spike(2 * HashBits(n, bits - 1));
+        Sequence<T> inCopy(in);
+
+        invoke_on_all_policies(test_any_of(), in.begin(), in.end(), is_equal_to<T>(spike), false);
+        invoke_on_all_policies(test_any_of(), in.cbegin(), in.cend(), is_equal_to<T>(spike), false);
+        EXPECT_EQ(in, inCopy, "any_of modified input sequence");
+        if (n > 0)
+        {
+            // Sprinkle in a hit
+            in[2 * n / 3] = spike;
+            invoke_on_all_policies(test_any_of(), in.begin(), in.end(), is_equal_to<T>(spike), true);
+            invoke_on_all_policies(test_any_of(), in.cbegin(), in.cend(), is_equal_to<T>(spike), true);
+
+            // Sprinkle in a few more hits
+            in[n / 2] = spike;
+            in[n / 3] = spike;
+            invoke_on_all_policies(test_any_of(), in.begin(), in.end(), is_equal_to<T>(spike), true);
+            invoke_on_all_policies(test_any_of(), in.cbegin(), in.cend(), is_equal_to<T>(spike), true);
+        }
+    }
+}
+
+struct test_non_const
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator iter)
+    {
+        auto is_even = [&](float64_t v) {
+            uint32_t i = (uint32_t)v;
+            return i % 2 == 0;
+        };
+        any_of(exec, iter, iter, non_const(is_even));
+    }
+};
+
+int
+main()
+{
+    test<int32_t>(8 * sizeof(int32_t));
+    test<uint16_t>(8 * sizeof(uint16_t));
+    test<float64_t>(53);
+#if !defined(_PSTL_ICC_16_17_TEST_REDUCTION_BOOL_TYPE_RELEASE_64_BROKEN)
+    test<bool>(1);
+#endif
+
+    test_algo_basic_single<int32_t>(run_for_rnd_fw<test_non_const>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.nonmodifying/count.pass.cpp b/pstl/test/std/algorithms/alg.nonmodifying/count.pass.cpp
new file mode 100644
index 0000000..e8eca02
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.nonmodifying/count.pass.cpp
@@ -0,0 +1,108 @@
+// -*- C++ -*-
+//===-- count.pass.cpp ----------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+// Tests for count and count_if
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct test_count
+{
+    template <typename Policy, typename Iterator, typename T>
+    void
+    operator()(Policy&& exec, Iterator first, Iterator last, T needle)
+    {
+        auto expected = std::count(first, last, needle);
+        auto result = std::count(exec, first, last, needle);
+        EXPECT_EQ(expected, result, "wrong count result");
+    }
+};
+
+struct test_count_if
+{
+    template <typename Policy, typename Iterator, typename Predicate>
+    void
+    operator()(Policy&& exec, Iterator first, Iterator last, Predicate pred)
+    {
+        auto expected = std::count_if(first, last, pred);
+        auto result = std::count_if(exec, first, last, pred);
+        EXPECT_EQ(expected, result, "wrong count_if result");
+    }
+};
+
+template <typename T>
+class IsEqual
+{
+    T value;
+
+  public:
+    IsEqual(T value_, OddTag) : value(value_) {}
+    bool
+    operator()(const T& x) const
+    {
+        return x == value;
+    }
+};
+
+template <typename In, typename T, typename Predicate, typename Convert>
+void
+test(T needle, Predicate pred, Convert convert)
+{
+    // Try sequences of various lengths.
+    for (size_t n = 0; n <= 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        Sequence<In> in(n, [=](size_t k) -> In {
+            // Sprinkle "42" and "50" early, so that short sequences have non-zero count.
+            return convert((n - k - 1) % 3 == 0 ? 42 : (n - k - 2) % 5 == 0 ? 50 : 3 * (int(k) % 1000 - 500));
+        });
+        invoke_on_all_policies(test_count(), in.begin(), in.end(), needle);
+        invoke_on_all_policies(test_count_if(), in.begin(), in.end(), pred);
+
+        invoke_on_all_policies(test_count(), in.cbegin(), in.cend(), needle);
+        invoke_on_all_policies(test_count_if(), in.cbegin(), in.cend(), pred);
+    }
+}
+
+struct test_non_const
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator iter)
+    {
+        auto is_even = [&](float64_t v) {
+            uint32_t i = (uint32_t)v;
+            return i % 2 == 0;
+        };
+        count_if(exec, iter, iter, non_const(is_even));
+    }
+};
+
+int
+main()
+{
+    test<int32_t>(42, IsEqual<int32_t>(50, OddTag()), [](int32_t j) { return j; });
+#if !defined(_PSTL_ICC_16_17_TEST_REDUCTION_RELEASE_BROKEN)
+    test<int32_t>(42, [](const int32_t&) { return true; }, [](int32_t j) { return j; });
+#endif
+    test<float64_t>(42, IsEqual<float64_t>(50, OddTag()), [](int32_t j) { return float64_t(j); });
+    test<Number>(Number(42, OddTag()), IsEqual<Number>(Number(50, OddTag()), OddTag()),
+                 [](int32_t j) { return Number(j, OddTag()); });
+
+    test_algo_basic_single<int32_t>(run_for_rnd_fw<test_non_const>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.nonmodifying/equal.pass.cpp b/pstl/test/std/algorithms/alg.nonmodifying/equal.pass.cpp
new file mode 100644
index 0000000..a6983ea
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.nonmodifying/equal.pass.cpp
@@ -0,0 +1,168 @@
+// -*- C++ -*-
+//===-- equal.pass.cpp ----------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+#define CPP14_ENABLED 0
+
+struct UserType
+{
+    size_t key;
+    float32_t f;
+    float64_t d;
+    int32_t i;
+
+    bool
+    operator()(UserType a, UserType b)
+    {
+        return a.key < b.key;
+    }
+    bool
+    operator<(UserType a)
+    {
+        return a.key < key;
+    }
+    bool
+    operator>=(UserType a)
+    {
+        return a.key <= key;
+    }
+    bool
+    operator<=(UserType a)
+    {
+        return a.key >= key;
+    }
+    bool
+    operator==(UserType a)
+    {
+        return a.key == key;
+    }
+    bool
+    operator==(UserType a) const
+    {
+        return a.key == key;
+    }
+    bool
+    operator!=(UserType a)
+    {
+        return a.key != key;
+    }
+    UserType operator!()
+    {
+        UserType tmp;
+        tmp.key = !key;
+        return tmp;
+    }
+    friend std::ostream&
+    operator<<(std::ostream& stream, const UserType a)
+    {
+        stream << a.key;
+        return stream;
+    }
+
+    UserType() : key(-1), f(0.0f), d(0.0), i(0) {}
+    UserType(size_t Number) : key(Number), f(0.0f), d(0.0), i(0) {}
+    UserType&
+    operator=(const UserType& other)
+    {
+        key = other.key;
+        return *this;
+    }
+    UserType(const UserType& other) : key(other.key), f(other.f), d(other.d), i(other.i) {}
+    UserType(UserType&& other) : key(other.key), f(other.f), d(other.d), i(other.i)
+    {
+        other.key = -1;
+        other.f = 0.0f;
+        other.d = 0.0;
+        other.i = 0;
+    }
+};
+
+struct test_one_policy
+{
+    template <typename ExecutionPolicy, typename Iterator1, typename Iterator2>
+    void
+    operator()(ExecutionPolicy&& exec, Iterator1 first1, Iterator1 last1, Iterator2 first2, bool is_true_equal)
+    {
+        using namespace std;
+
+        auto expected = equal(first1, last1, first2);
+        auto actual = equal(exec, first1, last1, first2);
+        EXPECT_EQ(expected, actual, "result for equal for random-access iterator, checking against std::equal()");
+
+        // testing bool
+        EXPECT_TRUE(is_true_equal == actual, "result for equal for random-access iterator, bool");
+
+//add C++14 equal symantics tests
+//add more cases for inCopy size less than in
+#if CPP14_ENABLED
+        auto actualr14 = std::equal(in.cbegin(), in.cend(), inCopy.cbegin(), inCopy.cend());
+        EXPECT_EQ(expected, actualr14, "result for equal for random-access iterator");
+#endif
+    }
+};
+
+template <typename T>
+void
+test(size_t bits)
+{
+    for (size_t n = 1; n <= 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+
+        // Sequence of odd values
+        Sequence<T> in(n, [bits](size_t k) { return T(2 * HashBits(k, bits - 1) ^ 1); });
+        Sequence<T> inCopy(in);
+
+        invoke_on_all_policies(test_one_policy(), in.begin(), in.end(), inCopy.begin(), true);
+        invoke_on_all_policies(test_one_policy(), in.cbegin(), in.cend(), inCopy.cbegin(), true);
+
+        // testing bool !equal()
+        inCopy[0] = !inCopy[0];
+        invoke_on_all_policies(test_one_policy(), in.begin(), in.end(), inCopy.begin(), false);
+        invoke_on_all_policies(test_one_policy(), in.cbegin(), in.cend(), inCopy.cbegin(), false);
+    }
+}
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename FirstIterator, typename SecondInterator>
+    void
+    operator()(Policy&& exec, FirstIterator first_iter, SecondInterator second_iter)
+    {
+        equal(exec, first_iter, first_iter, second_iter, second_iter, non_const(std::equal_to<T>()));
+    }
+};
+
+int
+main()
+{
+
+    test<int32_t>(8 * sizeof(int32_t));
+    test<uint16_t>(8 * sizeof(uint16_t));
+    test<float64_t>(53);
+#if !defined(_PSTL_ICC_16_17_TEST_REDUCTION_BOOL_TYPE_RELEASE_64_BROKEN)
+    test<bool>(1);
+#endif
+    test<UserType>(256);
+
+    test_algo_basic_double<int32_t>(run_for_rnd_fw<test_non_const<int32_t>>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.nonmodifying/find.pass.cpp b/pstl/test/std/algorithms/alg.nonmodifying/find.pass.cpp
new file mode 100644
index 0000000..54b25c27
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.nonmodifying/find.pass.cpp
@@ -0,0 +1,96 @@
+// -*- C++ -*-
+//===-- find.pass.cpp -----------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+// Tests for find
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct test_find
+{
+#if defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) ||                                                             \
+    defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) //dummy specialization by policy type, in case of broken configuration
+    template <typename Iterator, typename Value>
+    void
+    operator()(pstl::execution::unsequenced_policy, Iterator first, Iterator last, Value value)
+    {
+    }
+    template <typename Iterator, typename Value>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, Iterator first, Iterator last, Value value)
+    {
+    }
+#endif
+
+    template <typename Policy, typename Iterator, typename Value>
+    void
+    operator()(Policy&& exec, Iterator first, Iterator last, Value value)
+    {
+        auto i = std::find(first, last, value);
+        auto j = find(exec, first, last, value);
+        EXPECT_TRUE(i == j, "wrong return value from find");
+    }
+};
+
+template <typename T, typename Value, typename Hit, typename Miss>
+void
+test(Value value, Hit hit, Miss miss)
+{
+    // Try sequences of various lengths.
+    for (size_t n = 0; n <= 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        Sequence<T> in(n, [&](size_t k) -> T { return miss(n ^ k); });
+        // Try different find positions, including not found.
+        // By going backwards, we can add extra matches that are *not* supposed to be found.
+        // The decreasing exponential gives us O(n) total work for the loop since each find takes O(m) time.
+        for (size_t m = n; m > 0; m *= 0.6)
+        {
+            if (m < n)
+                in[m] = hit(n ^ m);
+            invoke_on_all_policies(test_find(), in.begin(), in.end(), value);
+            invoke_on_all_policies(test_find(), in.cbegin(), in.cend(), value);
+        }
+    }
+}
+
+// Type defined for sake of checking that std::find works with asymmetric ==.
+class Weird
+{
+    Number value;
+
+  public:
+    friend bool
+    operator==(Number x, Weird y)
+    {
+        return x == y.value;
+    }
+    Weird(int32_t val, OddTag) : value(val, OddTag()) {}
+};
+
+int
+main()
+{
+    // Note that the "hit" and "miss" functions here avoid overflow issues.
+    test<Number>(Weird(42, OddTag()), [](int32_t) { return Number(42, OddTag()); }, // hit
+                 [](int32_t j) { return Number(j == 42 ? 0 : j, OddTag()); });      // miss
+
+    // Test with value that is equal to two different bit patterns (-0.0 and 0.0)
+    test<float32_t>(-0.0, [](int32_t j) { return j & 1 ? 0.0 : -0.0; }, // hit
+                    [](int32_t j) { return j == 0 ? ~j : j; });         // miss
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.nonmodifying/find_end.pass.cpp b/pstl/test/std/algorithms/alg.nonmodifying/find_end.pass.cpp
new file mode 100644
index 0000000..ed0185f
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.nonmodifying/find_end.pass.cpp
@@ -0,0 +1,123 @@
+// -*- C++ -*-
+//===-- find_end.pass.cpp -------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct test_one_policy
+{
+#if defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) ||                                                             \
+    defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) //dummy specialization by policy type, in case of broken configuration
+    template <typename Iterator1, typename Iterator2, typename Predicate>
+    void
+    operator()(pstl::execution::unsequenced_policy, Iterator1 b, Iterator1 e, Iterator2 bsub, Iterator2 esub,
+               Predicate pred)
+    {
+    }
+    template <typename Iterator1, typename Iterator2, typename Predicate>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, Iterator1 b, Iterator1 e, Iterator2 bsub, Iterator2 esub,
+               Predicate pred)
+    {
+    }
+#endif
+
+    template <typename ExecutionPolicy, typename Iterator1, typename Iterator2, typename Predicate>
+    void
+    operator()(ExecutionPolicy&& exec, Iterator1 b, Iterator1 e, Iterator2 bsub, Iterator2 esub, Predicate pred)
+    {
+        using namespace std;
+        // For find_end
+        {
+            auto expected = find_end(b, e, bsub, esub, pred);
+            auto actual = find_end(exec, b, e, bsub, esub);
+            EXPECT_TRUE(actual == expected, "wrong return result from find_end");
+
+            actual = find_end(exec, b, e, bsub, esub, pred);
+            EXPECT_TRUE(actual == expected, "wrong return result from find_end with a predicate");
+        }
+
+        // For search
+        {
+            auto expected = search(b, e, bsub, esub, pred);
+            auto actual = search(exec, b, e, bsub, esub);
+            EXPECT_TRUE(actual == expected, "wrong return result from search");
+
+            actual = search(exec, b, e, bsub, esub, pred);
+            EXPECT_TRUE(actual == expected, "wrong return result from search with a predicate");
+        }
+    }
+};
+
+template <typename T>
+void
+test(const std::size_t bits)
+{
+
+    const std::size_t max_n1 = 1000;
+    const std::size_t max_n2 = (max_n1 * 10) / 8;
+    Sequence<T> in(max_n1, [bits](std::size_t) { return T(2 * HashBits(max_n1, bits - 1) ^ 1); });
+    Sequence<T> sub(max_n2, [bits](std::size_t) { return T(2 * HashBits(max_n1, bits - 1)); });
+    for (std::size_t n1 = 0; n1 <= max_n1; n1 = n1 <= 16 ? n1 + 1 : size_t(3.1415 * n1))
+    {
+        std::size_t sub_n[] = {0, 1, 3, n1, (n1 * 10) / 8};
+        std::size_t res[] = {0, 1, n1 / 2, n1};
+        for (auto n2 : sub_n)
+        {
+            for (auto r : res)
+            {
+                std::size_t i = r, isub = 0;
+                for (; i < n1 && isub < n2; ++i, ++isub)
+                    in[i] = sub[isub];
+                invoke_on_all_policies(test_one_policy(), in.begin(), in.begin() + n1, sub.begin(), sub.begin() + n2,
+                                       std::equal_to<T>());
+                invoke_on_all_policies(test_one_policy(), in.cbegin(), in.cbegin() + n1, sub.cbegin(),
+                                       sub.cbegin() + n2, std::equal_to<T>());
+            }
+        }
+    }
+}
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename FirstIterator, typename SecondInterator>
+    void
+    operator()(Policy&& exec, FirstIterator first_iter, SecondInterator second_iter)
+    {
+        invoke_if(exec, [&]() {
+            find_end(exec, first_iter, first_iter, second_iter, second_iter, non_const(std::equal_to<T>()));
+            search(exec, first_iter, first_iter, second_iter, second_iter, non_const(std::equal_to<T>()));
+        });
+    }
+};
+
+int
+main()
+{
+    test<int32_t>(8 * sizeof(int32_t));
+    test<uint16_t>(8 * sizeof(uint16_t));
+    test<float64_t>(53);
+#if !defined(_PSTL_ICC_16_17_TEST_REDUCTION_BOOL_TYPE_RELEASE_64_BROKEN)
+    test<bool>(1);
+#endif
+
+    test_algo_basic_double<int32_t>(run_for_rnd_fw<test_non_const<int32_t>>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.nonmodifying/find_first_of.pass.cpp b/pstl/test/std/algorithms/alg.nonmodifying/find_first_of.pass.cpp
new file mode 100644
index 0000000..5b4801e
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.nonmodifying/find_first_of.pass.cpp
@@ -0,0 +1,112 @@
+// -*- C++ -*-
+//===-- find_first_of.pass.cpp --------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct test_one_policy
+{
+#if defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) ||                                                             \
+    defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) //dummy specialization by policy type, in case of broken configuration
+    template <typename Iterator1, typename Iterator2, typename Predicate>
+    void
+    operator()(pstl::execution::unsequenced_policy, Iterator1 b, Iterator1 e, Iterator2 bsub, Iterator2 esub,
+               Predicate pred)
+    {
+    }
+    template <typename Iterator1, typename Iterator2, typename Predicate>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, Iterator1 b, Iterator1 e, Iterator2 bsub, Iterator2 esub,
+               Predicate pred)
+    {
+    }
+#endif
+
+    template <typename ExecutionPolicy, typename Iterator1, typename Iterator2, typename Predicate>
+    void
+    operator()(ExecutionPolicy&& exec, Iterator1 b, Iterator1 e, Iterator2 bsub, Iterator2 esub, Predicate pred)
+    {
+        using namespace std;
+        Iterator1 expected = find_first_of(b, e, bsub, esub, pred);
+        Iterator1 actual = find_first_of(exec, b, e, bsub, esub, pred);
+        EXPECT_TRUE(actual == expected, "wrong return result from find_first_of with a predicate");
+
+        expected = find_first_of(b, e, bsub, esub);
+        actual = find_first_of(exec, b, e, bsub, esub);
+        EXPECT_TRUE(actual == expected, "wrong return result from find_first_of");
+    }
+};
+
+template <typename T, typename Predicate>
+void
+test(Predicate pred)
+{
+
+    const std::size_t max_n1 = 1000;
+    const std::size_t max_n2 = (max_n1 * 10) / 8;
+    Sequence<T> in1(max_n1, [](std::size_t) { return T(1); });
+    Sequence<T> in2(max_n2, [](std::size_t) { return T(0); });
+    for (std::size_t n1 = 0; n1 <= max_n1; n1 = n1 <= 16 ? n1 + 1 : size_t(3.1415 * n1))
+    {
+        std::size_t sub_n[] = {0, 1, n1 / 3, n1, (n1 * 10) / 8};
+        for (const auto n2 : sub_n)
+        {
+            invoke_on_all_policies(test_one_policy(), in1.begin(), in1.begin() + n1, in2.data(), in2.data() + n2, pred);
+
+            in2[n2 / 2] = T(1);
+            invoke_on_all_policies(test_one_policy(), in1.cbegin(), in1.cbegin() + n1, in2.data(), in2.data() + n2,
+                                   pred);
+
+            if (n2 >= 3)
+            {
+                in2[2 * n2 / 3] = T(1);
+                invoke_on_all_policies(test_one_policy(), in1.cbegin(), in1.cbegin() + n1, in2.begin(),
+                                       in2.begin() + n2, pred);
+                in2[2 * n2 / 3] = T(0);
+            }
+            in2[n2 / 2] = T(0);
+        }
+    }
+    invoke_on_all_policies(test_one_policy(), in1.begin(), in1.begin() + max_n1 / 10, in1.data(),
+                           in1.data() + max_n1 / 10, pred);
+}
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename FirstIterator, typename SecondInterator>
+    void
+    operator()(Policy&& exec, FirstIterator first_iter, SecondInterator second_iter)
+    {
+        invoke_if(exec, [&]() {
+            find_first_of(exec, first_iter, first_iter, second_iter, second_iter, non_const(std::equal_to<T>()));
+        });
+    }
+};
+
+int
+main()
+{
+    test<int32_t>(std::equal_to<int32_t>());
+    test<uint16_t>(std::not_equal_to<uint16_t>());
+    test<float64_t>([](const float64_t x, const float64_t y) { return x * x == y * y; });
+
+    test_algo_basic_double<int32_t>(run_for_rnd_fw<test_non_const<int32_t>>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.nonmodifying/find_if.pass.cpp b/pstl/test/std/algorithms/alg.nonmodifying/find_if.pass.cpp
new file mode 100644
index 0000000..180d003
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.nonmodifying/find_if.pass.cpp
@@ -0,0 +1,109 @@
+// -*- C++ -*-
+//===-- find_if.pass.cpp --------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+// Tests for find_if and find_if_not
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct test_find_if
+{
+#if defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) ||                                                             \
+    defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) //dummy specialization by policy type, in case of broken configuration
+    template <typename Iterator, typename Predicate, typename NotPredicate>
+    void
+    operator()(pstl::execution::unsequenced_policy, Iterator first, Iterator last, Predicate pred,
+               NotPredicate not_pred)
+    {
+    }
+    template <typename Iterator, typename Predicate, typename NotPredicate>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, Iterator first, Iterator last, Predicate pred,
+               NotPredicate not_pred)
+    {
+    }
+#endif
+
+    template <typename Policy, typename Iterator, typename Predicate, typename NotPredicate>
+    void
+    operator()(Policy&& exec, Iterator first, Iterator last, Predicate pred, NotPredicate not_pred)
+    {
+        auto i = std::find_if(first, last, pred);
+        auto j = find_if(exec, first, last, pred);
+        EXPECT_TRUE(i == j, "wrong return value from find_if");
+        auto i_not = find_if_not(exec, first, last, not_pred);
+        EXPECT_TRUE(i_not == i, "wrong return value from find_if_not");
+    }
+};
+
+template <typename T, typename Predicate, typename Hit, typename Miss>
+void
+test(Predicate pred, Hit hit, Miss miss)
+{
+    auto not_pred = [pred](T x) { return !pred(x); };
+    // Try sequences of various lengths.
+    for (size_t n = 0; n <= 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        Sequence<T> in(n, [&](size_t k) -> T { return miss(n ^ k); });
+        // Try different find positions, including not found.
+        // By going backwards, we can add extra matches that are *not* supposed to be found.
+        // The decreasing exponential gives us O(n) total work for the loop since each find takes O(m) time.
+        for (size_t m = n; m > 0; m *= 0.6)
+        {
+            if (m < n)
+                in[m] = hit(n ^ m);
+            invoke_on_all_policies(test_find_if(), in.begin(), in.end(), pred, not_pred);
+            invoke_on_all_policies(test_find_if(), in.cbegin(), in.cend(), pred, not_pred);
+        }
+    }
+}
+
+struct test_non_const
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator iter)
+    {
+        auto is_even = [&](float64_t v) {
+            uint32_t i = (uint32_t)v;
+            return i % 2 == 0;
+        };
+
+        invoke_if(exec, [&]() {
+            find_if(exec, iter, iter, non_const(is_even));
+            find_if_not(exec, iter, iter, non_const(is_even));
+        });
+    }
+};
+
+int
+main()
+{
+#if !defined(_PSTL_ICC_17_TEST_MAC_RELEASE_32_BROKEN)
+    // Note that the "hit" and "miss" functions here avoid overflow issues.
+    test<Number>(IsMultiple(5, OddTag()), [](int32_t j) { return Number(j - j % 5, OddTag()); }, // hit
+                 [](int32_t j) { return Number(j % 5 == 0 ? j ^ 1 : j, OddTag()); });            // miss
+#endif
+
+    // Try type for which algorithm can really be vectorized.
+    test<float32_t>([](float32_t x) { return x >= 0; }, [](float32_t j) { return j * j; },
+                    [](float32_t j) { return -1 - j * j; });
+
+    test_algo_basic_single<int32_t>(run_for_rnd_fw<test_non_const>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.nonmodifying/for_each.pass.cpp b/pstl/test/std/algorithms/alg.nonmodifying/for_each.pass.cpp
new file mode 100644
index 0000000..14a0ad4
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.nonmodifying/for_each.pass.cpp
@@ -0,0 +1,102 @@
+// -*- C++ -*-
+//===-- for_each.pass.cpp -------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+template <typename Type>
+struct Gen
+{
+    Type
+    operator()(std::size_t k)
+    {
+        return Type(k % 5 != 1 ? 3 * k - 7 : 0);
+    };
+};
+
+template <typename T>
+struct Flip
+{
+    int32_t val;
+    Flip(int32_t y) : val(y) {}
+    T
+    operator()(T& x) const
+    {
+        return x = val - x;
+    }
+};
+
+struct test_one_policy
+{
+    template <typename Policy, typename Iterator, typename Size>
+    void
+    operator()(Policy&& exec, Iterator first, Iterator last, Iterator expected_first, Iterator expected_last, Size n)
+    {
+        typedef typename std::iterator_traits<Iterator>::value_type T;
+
+        // Try for_each
+        std::for_each(expected_first, expected_last, Flip<T>(1));
+        for_each(exec, first, last, Flip<T>(1));
+        EXPECT_EQ_N(expected_first, first, n, "wrong effect from for_each");
+
+        // Try for_each_n
+        std::for_each_n(std::execution::seq, expected_first, n, Flip<T>(1));
+        for_each_n(exec, first, n, Flip<T>(1));
+        EXPECT_EQ_N(expected_first, first, n, "wrong effect from for_each_n");
+    }
+};
+
+template <typename T>
+void
+test()
+{
+    for (size_t n = 0; n <= 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        Sequence<T> inout(n, Gen<T>());
+        Sequence<T> expected(n, Gen<T>());
+        invoke_on_all_policies(test_one_policy(), inout.begin(), inout.end(), expected.begin(), expected.end(),
+                               inout.size());
+    }
+}
+
+struct test_non_const
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator iter)
+    {
+        invoke_if(exec, [&]() {
+            auto f = [](typename std::iterator_traits<Iterator>::reference x) { x = x + 1; };
+
+            for_each(exec, iter, iter, non_const(f));
+            for_each_n(exec, iter, 0, non_const(f));
+        });
+    }
+};
+
+int
+main()
+{
+    test<int32_t>();
+    test<uint16_t>();
+    test<float64_t>();
+
+    test_algo_basic_single<int32_t>(run_for_rnd_fw<test_non_const>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.nonmodifying/mismatch.pass.cpp b/pstl/test/std/algorithms/alg.nonmodifying/mismatch.pass.cpp
new file mode 100644
index 0000000..4d83ad6
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.nonmodifying/mismatch.pass.cpp
@@ -0,0 +1,132 @@
+// -*- C++ -*-
+//===-- mismatch.pass.cpp -------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct test_mismatch
+{
+    template <typename Policy, typename Iterator1, typename Iterator2>
+    void
+    operator()(Policy&& exec, Iterator1 first1, Iterator1 last1, Iterator2 first2)
+    {
+        using namespace std;
+        typedef typename iterator_traits<Iterator1>::value_type T;
+        {
+            const auto expected = std::mismatch(first1, last1, first2, std::equal_to<T>());
+            const auto res3 = mismatch(exec, first1, last1, first2, std::equal_to<T>());
+            EXPECT_TRUE(expected == res3, "wrong return result from mismatch");
+            const auto res4 = mismatch(exec, first1, last1, first2);
+            EXPECT_TRUE(expected == res4, "wrong return result from mismatch");
+        }
+    }
+    template <typename Policy, typename Iterator1, typename Iterator2>
+    void
+    operator()(Policy&& exec, Iterator1 first1, Iterator1 last1, Iterator2 first2, Iterator2 last2)
+    {
+        using namespace std;
+        typedef typename iterator_traits<Iterator1>::value_type T;
+        {
+            const auto expected = mismatch(std::execution::seq, first1, last1, first2, last2, std::equal_to<T>());
+            const auto res1 = mismatch(exec, first1, last1, first2, last2, std::equal_to<T>());
+            EXPECT_TRUE(expected == res1, "wrong return result from mismatch");
+            const auto res2 = mismatch(exec, first1, last1, first2, last2);
+            EXPECT_TRUE(expected == res2, "wrong return result from mismatch");
+        }
+    }
+};
+
+template <typename T>
+void
+test_mismatch_by_type()
+{
+    using namespace std;
+    for (size_t size = 0; size <= 100000; size = size <= 16 ? size + 1 : size_t(3.1415 * size))
+    {
+        const T val = T(-1);
+        Sequence<T> in(size, [](size_t v) -> T { return T(v % 100); });
+        {
+            Sequence<T> in2(in);
+            invoke_on_all_policies(test_mismatch(), in.begin(), in.end(), in2.begin(), in2.end());
+            invoke_on_all_policies(test_mismatch(), in.begin(), in.end(), in2.begin());
+
+            const size_t min_size = 3;
+            if (size > min_size)
+            {
+                const size_t idx_for_1 = size / min_size;
+                in[idx_for_1] = val, in[idx_for_1 + 1] = val, in[idx_for_1 + 2] = val;
+                invoke_on_all_policies(test_mismatch(), in.begin(), in.end(), in2.begin(), in2.end());
+                invoke_on_all_policies(test_mismatch(), in.begin(), in.end(), in2.begin());
+            }
+
+            const size_t idx_for_2 = 500;
+            if (size >= idx_for_2 - 1)
+            {
+                in2[size / idx_for_2] = val;
+                invoke_on_all_policies(test_mismatch(), in.cbegin(), in.cend(), in2.cbegin(), in2.cend());
+                invoke_on_all_policies(test_mismatch(), in.cbegin(), in.cend(), in2.cbegin());
+            }
+        }
+        {
+            Sequence<T> in2(100, [](size_t v) -> T { return T(v); });
+            invoke_on_all_policies(test_mismatch(), in2.begin(), in2.end(), in.begin(), in.end());
+            //  We can't call std::mismatch with semantic below when size of second sequence less than size of first sequence
+            if (in2.size() <= in.size())
+                invoke_on_all_policies(test_mismatch(), in2.begin(), in2.end(), in.begin());
+
+            const size_t idx = 97;
+            in2[idx] = val;
+            in2[idx + 1] = val;
+            invoke_on_all_policies(test_mismatch(), in.cbegin(), in.cend(), in2.cbegin(), in2.cend());
+            if (in.size() <= in2.size())
+                invoke_on_all_policies(test_mismatch(), in.cbegin(), in.cend(), in2.cbegin());
+        }
+        {
+            Sequence<T> in2({});
+            invoke_on_all_policies(test_mismatch(), in2.begin(), in2.end(), in.begin(), in.end());
+
+            invoke_on_all_policies(test_mismatch(), in.cbegin(), in.cend(), in2.cbegin(), in2.cend());
+            if (in.size() == 0)
+                invoke_on_all_policies(test_mismatch(), in.cbegin(), in.cend(), in2.cbegin());
+        }
+    }
+}
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename FirstIterator, typename SecondInterator>
+    void
+    operator()(Policy&& exec, FirstIterator first_iter, SecondInterator second_iter)
+    {
+        mismatch(exec, first_iter, first_iter, second_iter, second_iter, non_const(std::less<T>()));
+    }
+};
+
+int
+main()
+{
+
+    test_mismatch_by_type<int32_t>();
+    test_mismatch_by_type<float64_t>();
+    test_mismatch_by_type<Wrapper<int32_t>>();
+
+    test_algo_basic_double<int32_t>(run_for_rnd_fw<test_non_const<int32_t>>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.nonmodifying/none_of.pass.cpp b/pstl/test/std/algorithms/alg.nonmodifying/none_of.pass.cpp
new file mode 100644
index 0000000..dbdcd54
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.nonmodifying/none_of.pass.cpp
@@ -0,0 +1,101 @@
+// -*- C++ -*-
+//===-- none_of.pass.cpp --------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+/*
+  TODO: consider implementing the following tests for a better code coverage
+  - correctness
+  - bad input argument (if applicable)
+  - data corruption around/of input and output
+  - correctly work with nested parallelism
+  - check that algorithm does not require anything more than is described in its requirements section
+*/
+
+using namespace TestUtils;
+
+struct test_none_of
+{
+    template <typename ExecutionPolicy, typename Iterator, typename Predicate>
+    void
+    operator()(ExecutionPolicy&& exec, Iterator begin, Iterator end, Predicate pred, bool expected)
+    {
+
+        auto actualr = std::none_of(exec, begin, end, pred);
+        EXPECT_EQ(expected, actualr, "result for none_of");
+    }
+};
+
+template <typename T>
+void
+test(size_t bits)
+{
+    for (size_t n = 0; n <= 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+
+        // Sequence of odd values
+        Sequence<T> in(n, [n, bits](size_t) { return T(2 * HashBits(n, bits - 1) ^ 1); });
+
+        // Even value, or false when T is bool.
+        T spike(2 * HashBits(n, bits - 1));
+
+        invoke_on_all_policies(test_none_of(), in.begin(), in.end(), is_equal_to<T>(spike), true);
+        invoke_on_all_policies(test_none_of(), in.cbegin(), in.cend(), is_equal_to<T>(spike), true);
+        if (n > 0)
+        {
+            // Sprinkle in a hit
+            in[2 * n / 3] = spike;
+            invoke_on_all_policies(test_none_of(), in.begin(), in.end(), is_equal_to<T>(spike), false);
+            invoke_on_all_policies(test_none_of(), in.cbegin(), in.cend(), is_equal_to<T>(spike), false);
+
+            // Sprinkle in a few more hits
+            in[n / 3] = spike;
+            in[n / 2] = spike;
+            invoke_on_all_policies(test_none_of(), in.begin(), in.end(), is_equal_to<T>(spike), false);
+            invoke_on_all_policies(test_none_of(), in.cbegin(), in.cend(), is_equal_to<T>(spike), false);
+        }
+    }
+}
+
+struct test_non_const
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator iter)
+    {
+        auto is_even = [&](float64_t v) {
+            uint32_t i = (uint32_t)v;
+            return i % 2 == 0;
+        };
+        none_of(exec, iter, iter, non_const(is_even));
+    }
+};
+
+int
+main()
+{
+    test<int32_t>(8 * sizeof(int32_t));
+    test<uint16_t>(8 * sizeof(uint16_t));
+    test<float64_t>(53);
+#if !defined(_PSTL_ICC_16_17_TEST_REDUCTION_BOOL_TYPE_RELEASE_64_BROKEN)
+    test<bool>(1);
+#endif
+
+    test_algo_basic_single<int32_t>(run_for_rnd_fw<test_non_const>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.nonmodifying/nth_element.pass.cpp b/pstl/test/std/algorithms/alg.nonmodifying/nth_element.pass.cpp
new file mode 100644
index 0000000..f3e43da
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.nonmodifying/nth_element.pass.cpp
@@ -0,0 +1,175 @@
+// -*- C++ -*-
+//===-- nth_element.pass.cpp ----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <iostream>
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+// User defined type with minimal requirements
+template <typename T>
+struct DataType
+{
+    explicit DataType(int32_t k) : my_val(k) {}
+    DataType(DataType&& input)
+    {
+        my_val = std::move(input.my_val);
+        input.my_val = T(0);
+    }
+    DataType&
+    operator=(DataType&& input)
+    {
+        my_val = std::move(input.my_val);
+        input.my_val = T(0);
+        return *this;
+    }
+    T
+    get_val() const
+    {
+        return my_val;
+    }
+
+    friend std::ostream&
+    operator<<(std::ostream& stream, const DataType<T>& input)
+    {
+        return stream << input.my_val;
+    }
+
+  private:
+    T my_val;
+};
+
+template <typename T>
+bool
+is_equal(const DataType<T>& x, const DataType<T>& y)
+{
+    return x.get_val() == y.get_val();
+}
+
+template <typename T>
+bool
+is_equal(const T& x, const T& y)
+{
+    return x == y;
+}
+
+struct test_one_policy
+{
+#if defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) ||                                                             \
+    defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) // dummy specialization by policy type, in case of broken configuration
+    template <typename Iterator1, typename Size, typename Generator1, typename Generator2, typename Compare>
+    typename std::enable_if<is_same_iterator_category<Iterator1, std::random_access_iterator_tag>::value, void>::type
+    operator()(pstl::execution::unsequenced_policy, Iterator1 first1, Iterator1 last1, Iterator1 first2,
+               Iterator1 last2, Size n, Size m, Generator1 generator1, Generator2 generator2, Compare comp)
+    {
+    }
+    template <typename Iterator1, typename Size, typename Generator1, typename Generator2, typename Compare>
+    typename std::enable_if<is_same_iterator_category<Iterator1, std::random_access_iterator_tag>::value, void>::type
+    operator()(pstl::execution::parallel_unsequenced_policy, Iterator1 first1, Iterator1 last1, Iterator1 first2,
+               Iterator1 last2, Size n, Size m, Generator1 generator1, Generator2 generator2, Compare comp)
+    {
+    }
+#endif
+
+    // nth_element works only with random access iterators
+    template <typename Policy, typename Iterator1, typename Size, typename Generator1, typename Generator2,
+              typename Compare>
+    typename std::enable_if<is_same_iterator_category<Iterator1, std::random_access_iterator_tag>::value, void>::type
+    operator()(Policy&& exec, Iterator1 first1, Iterator1 last1, Iterator1 first2, Iterator1 last2, Size n, Size m,
+               Generator1 generator1, Generator2 generator2, Compare comp)
+    {
+
+        using T = typename std::iterator_traits<Iterator1>::value_type;
+        const Iterator1 mid1 = std::next(first1, m);
+        const Iterator1 mid2 = std::next(first2, m);
+
+        fill_data(first1, mid1, generator1);
+        fill_data(mid1, last1, generator2);
+        fill_data(first2, mid2, generator1);
+        fill_data(mid2, last2, generator2);
+        std::nth_element(first1, mid1, last1, comp);
+        std::nth_element(exec, first2, mid2, last2, comp);
+        if (m > 0 && m < n)
+        {
+            EXPECT_TRUE(is_equal(*mid1, *mid2), "wrong result from nth_element with predicate");
+        }
+        EXPECT_TRUE(std::find_first_of(first2, mid2, mid2, last2, [comp](T& x, T& y) { return comp(y, x); }) == mid2,
+                    "wrong effect from nth_element with predicate");
+    }
+
+    template <typename Policy, typename Iterator1, typename Size, typename Generator1, typename Generator2,
+              typename Compare>
+    typename std::enable_if<!is_same_iterator_category<Iterator1, std::random_access_iterator_tag>::value, void>::type
+    operator()(Policy&&, Iterator1, Iterator1, Iterator1, Iterator1, Size, Size, Generator1, Generator2, Compare)
+    {
+    }
+};
+
+template <typename T, typename Generator1, typename Generator2, typename Compare>
+void
+test_by_type(Generator1 generator1, Generator2 generator2, Compare comp)
+{
+    using namespace std;
+    size_t max_size = 10000;
+    Sequence<T> in1(max_size, [](size_t v) { return T(v); });
+    Sequence<T> exp(max_size, [](size_t v) { return T(v); });
+    size_t m;
+
+    for (size_t n = 0; n <= max_size; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        m = 0;
+        invoke_on_all_policies(test_one_policy(), exp.begin(), exp.begin() + n, in1.begin(), in1.begin() + n, n, m,
+                               generator1, generator2, comp);
+        m = n / 7;
+        invoke_on_all_policies(test_one_policy(), exp.begin(), exp.begin() + n, in1.begin(), in1.begin() + n, n, m,
+                               generator1, generator2, comp);
+        m = 3 * n / 5;
+        invoke_on_all_policies(test_one_policy(), exp.begin(), exp.begin() + n, in1.begin(), in1.begin() + n, n, m,
+                               generator1, generator2, comp);
+    }
+    invoke_on_all_policies(test_one_policy(), exp.begin(), exp.begin() + max_size, in1.begin(), in1.begin() + max_size,
+                           max_size, max_size, generator1, generator2, comp);
+}
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator iter)
+    {
+        invoke_if(exec, [&]() { nth_element(exec, iter, iter, iter, non_const(std::less<T>())); });
+    }
+};
+
+int
+main()
+{
+    test_by_type<int32_t>([](int32_t i) { return 10 * i; }, [](int32_t i) { return i + 1; }, std::less<int32_t>());
+    test_by_type<int32_t>([](int32_t) { return 0; }, [](int32_t) { return 0; }, std::less<int32_t>());
+
+    test_by_type<float64_t>([](int32_t i) { return -2 * i; }, [](int32_t i) { return -(2 * i + 1); },
+                            [](const float64_t x, const float64_t y) { return x > y; });
+
+    test_by_type<DataType<float32_t>>(
+        [](int32_t i) { return DataType<float32_t>(2 * i + 1); }, [](int32_t i) { return DataType<float32_t>(2 * i); },
+        [](const DataType<float32_t>& x, const DataType<float32_t>& y) { return x.get_val() < y.get_val(); });
+
+    test_algo_basic_single<int32_t>(run_for_rnd<test_non_const<int32_t>>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.nonmodifying/search_n.pass.cpp b/pstl/test/std/algorithms/alg.nonmodifying/search_n.pass.cpp
new file mode 100644
index 0000000..573f364
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.nonmodifying/search_n.pass.cpp
@@ -0,0 +1,109 @@
+// -*- C++ -*-
+//===-- search_n.pass.cpp -------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct test_one_policy
+{
+#if defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) ||                                                             \
+    defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) //dummy specialization by policy type, in case of broken configuration
+    template <typename Iterator, typename Size, typename T, typename Predicate>
+    void
+    operator()(pstl::execution::unsequenced_policy, Iterator b, Iterator e, Size count, const T& value, Predicate pred)
+    {
+    }
+    template <typename Iterator, typename Size, typename T, typename Predicate>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, Iterator b, Iterator e, Size count, const T& value,
+               Predicate pred)
+    {
+    }
+#endif
+
+    template <typename ExecutionPolicy, typename Iterator, typename Size, typename T, typename Predicate>
+    void
+    operator()(ExecutionPolicy&& exec, Iterator b, Iterator e, Size count, const T& value, Predicate pred)
+    {
+        using namespace std;
+        auto expected = search_n(b, e, count, value, pred);
+        auto actual = search_n(exec, b, e, count, value);
+        EXPECT_TRUE(actual == expected, "wrong return result from search_n");
+
+        actual = search_n(exec, b, e, count, value, pred);
+        EXPECT_TRUE(actual == expected, "wrong return result from search_n with a predicate");
+    }
+};
+
+template <typename T>
+void
+test()
+{
+
+    const std::size_t max_n1 = 100000;
+    const T value = T(1);
+    for (std::size_t n1 = 0; n1 <= max_n1; n1 = n1 <= 16 ? n1 + 1 : size_t(3.1415 * n1))
+    {
+        std::size_t sub_n[] = {0, 1, 3, n1, (n1 * 10) / 8};
+        std::size_t res[] = {0, 1, n1 / 2, n1};
+        for (auto n2 : sub_n)
+        {
+            // Some of standard libraries return "first" in this case. We return "last" according to the standard
+            if (n2 == 0)
+            {
+                continue;
+            }
+            for (auto r : res)
+            {
+                Sequence<T> in(n1, [](std::size_t) { return T(0); });
+                std::size_t i = r, isub = 0;
+                for (; i < n1 && isub < n2; ++i, ++isub)
+                    in[i] = value;
+
+                invoke_on_all_policies(test_one_policy(), in.begin(), in.begin() + n1, n2, value, std::equal_to<T>());
+                invoke_on_all_policies(test_one_policy(), in.cbegin(), in.cbegin() + n1, n2, value, std::equal_to<T>());
+            }
+        }
+    }
+}
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator iter)
+    {
+        invoke_if(exec, [&]() { search_n(exec, iter, iter, 0, T(0), non_const(std::equal_to<T>())); });
+    }
+};
+
+int
+main()
+{
+    test<int32_t>();
+    test<uint16_t>();
+    test<float64_t>();
+#if !defined(_PSTL_ICC_16_17_TEST_REDUCTION_BOOL_TYPE_RELEASE_64_BROKEN)
+    test<bool>();
+#endif
+
+    test_algo_basic_single<int32_t>(run_for_rnd_fw<test_non_const<int32_t>>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.sorting/alg.heap.operations/is_heap.pass.cpp b/pstl/test/std/algorithms/alg.sorting/alg.heap.operations/is_heap.pass.cpp
new file mode 100644
index 0000000..08eca8e
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.sorting/alg.heap.operations/is_heap.pass.cpp
@@ -0,0 +1,146 @@
+// -*- C++ -*-
+//===-- is_heap.pass.cpp --------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+// Tests for is_heap, is_heap_until
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+#include <iostream>
+
+using namespace TestUtils;
+
+struct WithCmpOp
+{
+    int32_t _first;
+    int32_t _second;
+    WithCmpOp() : _first(0), _second(0){};
+    explicit WithCmpOp(int32_t x) : _first(x), _second(x){};
+    bool
+    operator<(const WithCmpOp& rhs) const
+    {
+        return this->_first < rhs._first;
+    }
+};
+
+struct test_is_heap
+{
+#if defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) ||                                                             \
+    defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) //dummy specialization by policy type, in case of broken configuration
+    template <typename Iterator, typename Predicate>
+    typename std::enable_if<is_same_iterator_category<Iterator, std::random_access_iterator_tag>::value, void>::type
+    operator()(pstl::execution::unsequenced_policy, Iterator first, Iterator last, Predicate pred)
+    {
+    }
+    template <typename Iterator, typename Predicate>
+    typename std::enable_if<is_same_iterator_category<Iterator, std::random_access_iterator_tag>::value, void>::type
+    operator()(pstl::execution::parallel_unsequenced_policy, Iterator first, Iterator last, Predicate pred)
+    {
+    }
+#endif
+
+    template <typename Policy, typename Iterator, typename Predicate>
+    typename std::enable_if<is_same_iterator_category<Iterator, std::random_access_iterator_tag>::value, void>::type
+    operator()(Policy&& exec, Iterator first, Iterator last, Predicate pred)
+    {
+        using namespace std;
+        // is_heap
+        {
+            bool expected = is_heap(first, last);
+            bool actual = is_heap(exec, first, last);
+            EXPECT_TRUE(expected == actual, "wrong return value from is_heap");
+        }
+        // is_heap with predicate
+        {
+            bool expected = is_heap(first, last, pred);
+            bool actual = is_heap(exec, first, last, pred);
+            EXPECT_TRUE(expected == actual, "wrong return value from is_heap with predicate");
+        }
+        // is_heap_until
+        {
+            Iterator expected = is_heap_until(first, last);
+            Iterator actual = is_heap_until(exec, first, last);
+            EXPECT_TRUE(expected == actual, "wrong return value from is_heap_until");
+        }
+        // is_heap_until with predicate
+        {
+            const Iterator expected = is_heap_until(first, last, pred);
+            const auto y = std::distance(first, expected);
+            const Iterator actual = is_heap_until(exec, first, last, pred);
+            const auto x = std::distance(first, actual);
+            EXPECT_TRUE(expected == actual, "wrong return value from is_heap_until with predicate");
+            EXPECT_EQ(x, y, "both iterators should be the same distance away from 'first'");
+        }
+    }
+
+    // is_heap, is_heap_until works only with random access iterators
+    template <typename Policy, typename Iterator, typename Predicate>
+    typename std::enable_if<!is_same_iterator_category<Iterator, std::random_access_iterator_tag>::value, void>::type
+    operator()(Policy&&, Iterator, Iterator, Predicate)
+    {
+    }
+};
+
+template <typename T, typename Comp>
+void
+test_is_heap_by_type(Comp comp)
+{
+    using namespace std;
+
+    const size_t max_size = 100000;
+    for (size_t n = 0; n <= max_size; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        Sequence<T> in(n, [](size_t v) -> T { return T(v); });
+
+        invoke_on_all_policies(test_is_heap(), in.begin(), in.end(), comp);
+
+        std::make_heap(in.begin(), in.begin() + n / 4, comp);
+        invoke_on_all_policies(test_is_heap(), in.cbegin(), in.cend(), comp);
+
+        std::make_heap(in.begin(), in.begin() + n / 3, comp);
+        invoke_on_all_policies(test_is_heap(), in.begin(), in.end(), comp);
+
+        std::make_heap(in.begin(), in.end(), comp);
+        invoke_on_all_policies(test_is_heap(), in.cbegin(), in.cend(), comp);
+    }
+
+    Sequence<T> in(max_size / 10, [](size_t) -> T { return T(1); });
+    invoke_on_all_policies(test_is_heap(), in.begin(), in.end(), comp);
+}
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator iter)
+    {
+        invoke_if(exec, [&]() {
+            is_heap(exec, iter, iter, non_const(std::less<T>()));
+            is_heap_until(exec, iter, iter, non_const(std::less<T>()));
+        });
+    }
+};
+
+int
+main()
+{
+    test_is_heap_by_type<float32_t>(std::greater<float32_t>());
+    test_is_heap_by_type<WithCmpOp>(std::less<WithCmpOp>());
+    test_is_heap_by_type<uint64_t>([](uint64_t x, uint64_t y) { return x % 100 < y % 100; });
+
+    test_algo_basic_single<int32_t>(run_for_rnd<test_non_const<int32_t>>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.sorting/alg.lex.comparison/lexicographical_compare.pass.cpp b/pstl/test/std/algorithms/alg.sorting/alg.lex.comparison/lexicographical_compare.pass.cpp
new file mode 100644
index 0000000..cb92057
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.sorting/alg.lex.comparison/lexicographical_compare.pass.cpp
@@ -0,0 +1,175 @@
+// -*- C++ -*-
+//===-- lexicographical_compare.pass.cpp ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <iostream>
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct test_one_policy
+{
+
+    template <typename ExecutionPolicy, typename Iterator1, typename Iterator2, typename Predicate>
+    void
+    operator()(ExecutionPolicy&& exec, Iterator1 begin1, Iterator1 end1, Iterator2 begin2, Iterator2 end2,
+               Predicate pred)
+    {
+        const bool expected = std::lexicographical_compare(begin1, end1, begin2, end2, pred);
+        const bool actual = std::lexicographical_compare(exec, begin1, end1, begin2, end2, pred);
+        EXPECT_TRUE(actual == expected, "wrong return result from lexicographical compare with predicate");
+    }
+
+    template <typename ExecutionPolicy, typename Iterator1, typename Iterator2>
+    void
+    operator()(ExecutionPolicy&& exec, Iterator1 begin1, Iterator1 end1, Iterator2 begin2, Iterator2 end2)
+    {
+        const bool expected = std::lexicographical_compare(begin1, end1, begin2, end2);
+        const bool actual = std::lexicographical_compare(exec, begin1, end1, begin2, end2);
+        EXPECT_TRUE(actual == expected, "wrong return result from lexicographical compare without predicate");
+    }
+};
+
+template <typename T1, typename T2, typename Predicate>
+void
+test(Predicate pred)
+{
+
+    const std::size_t max_n = 1000000;
+    Sequence<T1> in1(max_n, [](std::size_t k) { return T1(k); });
+    Sequence<T2> in2(2 * max_n, [](std::size_t k) { return T2(k); });
+
+    std::size_t n2;
+
+    // Test case: Call algorithm's version without predicate.
+    invoke_on_all_policies(test_one_policy(), in1.cbegin(), in1.cbegin() + max_n, in2.cbegin() + 3 * max_n / 10,
+                           in2.cbegin() + 5 * max_n / 10);
+
+    // Test case: If one range is a prefix of another, the shorter range is lexicographically less than the other.
+    std::size_t max_n2 = max_n / 10;
+    invoke_on_all_policies(test_one_policy(), in1.begin(), in1.begin() + max_n, in2.cbegin(), in2.cbegin() + max_n2,
+                           pred);
+    invoke_on_all_policies(test_one_policy(), in1.begin(), in1.begin() + max_n, in2.begin() + max_n2,
+                           in2.begin() + 3 * max_n2, pred);
+
+    // Test case: If one range is a prefix of another, the shorter range is lexicographically less than the other.
+    max_n2 = 2 * max_n;
+    invoke_on_all_policies(test_one_policy(), in1.cbegin(), in1.cbegin() + max_n, in2.begin(), in2.begin() + max_n2,
+                           pred);
+
+    for (std::size_t n1 = 0; n1 <= max_n; n1 = n1 <= 16 ? n1 + 1 : std::size_t(3.1415 * n1))
+    {
+        // Test case: If two ranges have equivalent elements and are of the same length, then the ranges are lexicographically equal.
+        n2 = n1;
+        invoke_on_all_policies(test_one_policy(), in1.begin(), in1.begin() + n1, in2.begin(), in2.begin() + n2, pred);
+
+        n2 = n1;
+        // Test case: two ranges have different elements and are of the same length (second sequence less than first)
+        std::size_t ind = n1 / 2;
+        in2[ind] = T2(-1);
+        invoke_on_all_policies(test_one_policy(), in1.begin(), in1.begin() + n1, in2.begin(), in2.begin() + n2, pred);
+        in2[ind] = T2(ind);
+
+        // Test case: two ranges have different elements and are of the same length (first sequence less than second)
+        ind = n1 / 5;
+        in1[ind] = T1(-1);
+        invoke_on_all_policies(test_one_policy(), in1.begin(), in1.begin() + n1, in2.cbegin(), in2.cbegin() + n2, pred);
+        in1[ind] = T1(ind);
+    }
+}
+
+template <typename Predicate>
+void
+test_string(Predicate pred)
+{
+
+    const std::size_t max_n = 1000000;
+    std::string in1 = "";
+    std::string in2 = "";
+    for (std::size_t n1 = 0; n1 <= max_n; ++n1)
+    {
+        in1 += n1;
+    }
+
+    for (std::size_t n1 = 0; n1 <= 2 * max_n; ++n1)
+    {
+        in2 += n1;
+    }
+
+    std::size_t n2;
+
+    for (std::size_t n1 = 0; n1 < in1.size(); n1 = n1 <= 16 ? n1 + 1 : std::size_t(3.1415 * n1))
+    {
+        // Test case: If two ranges have equivalent elements and are of the same length, then the ranges are lexicographically equal.
+        n2 = n1;
+        invoke_on_all_policies(test_one_policy(), in1.begin(), in1.begin() + n1, in2.begin(), in2.begin() + n2, pred);
+
+        n2 = n1;
+        // Test case: two ranges have different elements and are of the same length (second sequence less than first)
+        in2[n1 / 2] = 'a';
+        invoke_on_all_policies(test_one_policy(), in1.begin(), in1.begin() + n1, in2.begin(), in2.begin() + n2, pred);
+
+        // Test case: two ranges have different elements and are of the same length (first sequence less than second)
+        in1[n1 / 5] = 'a';
+        invoke_on_all_policies(test_one_policy(), in1.begin(), in1.begin() + n1, in2.cbegin(), in2.cbegin() + n2, pred);
+    }
+    invoke_on_all_policies(test_one_policy(), in1.cbegin(), in1.cbegin() + max_n, in2.cbegin() + 3 * max_n / 10,
+                           in2.cbegin() + 5 * max_n / 10);
+}
+
+template <typename T>
+struct LocalWrapper
+{
+    explicit LocalWrapper(std::size_t k) : my_val(k) {}
+    bool
+    operator<(const LocalWrapper<T>& w) const
+    {
+        return my_val < w.my_val;
+    }
+
+  private:
+    T my_val;
+};
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename FirstIterator, typename SecondInterator>
+    void
+    operator()(Policy&& exec, FirstIterator first_iter, SecondInterator second_iter)
+    {
+        invoke_if(exec, [&]() {
+            lexicographical_compare(exec, first_iter, first_iter, second_iter, second_iter, non_const(std::less<T>()));
+        });
+    }
+};
+
+int
+main()
+{
+    test<uint16_t, float64_t>(std::less<float64_t>());
+    test<float32_t, int32_t>(std::greater<float32_t>());
+#if !defined(_PSTL_ICC_18_TEST_EARLY_EXIT_AVX_RELEASE_BROKEN)
+    test<float64_t, int32_t>([](const float64_t x, const int32_t y) { return x * x < y * y; });
+#endif
+    test<LocalWrapper<int32_t>, LocalWrapper<int32_t>>(
+        [](const LocalWrapper<int32_t>& x, const LocalWrapper<int32_t>& y) { return x < y; });
+    test_string([](const char x, const char y) { return x < y; });
+
+    test_algo_basic_double<int32_t>(run_for_rnd_fw<test_non_const<int32_t>>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.sorting/alg.min.max/minmax_element.pass.cpp b/pstl/test/std/algorithms/alg.sorting/alg.min.max/minmax_element.pass.cpp
new file mode 100644
index 0000000..715b250
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.sorting/alg.min.max/minmax_element.pass.cpp
@@ -0,0 +1,192 @@
+// -*- C++ -*-
+//===-- minmax_element.pass.cpp -------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+#include <set>
+#include <cmath>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct check_minelement
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator begin, Iterator end)
+    {
+        typedef typename std::iterator_traits<Iterator>::value_type T;
+        const Iterator expect = std::min_element(begin, end);
+        const Iterator result = std::min_element(exec, begin, end);
+        const Iterator result_pred = std::min_element(exec, begin, end, std::less<T>());
+        EXPECT_TRUE(expect == result, "wrong return result from min_element");
+        EXPECT_TRUE(expect == result_pred, "wrong return result from min_element");
+    }
+};
+
+struct check_maxelement
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator begin, Iterator end)
+    {
+        typedef typename std::iterator_traits<Iterator>::value_type T;
+        const Iterator expect = std::max_element(begin, end);
+        const Iterator result = std::max_element(exec, begin, end);
+        const Iterator result_pred = std::max_element(exec, begin, end, std::less<T>());
+        EXPECT_TRUE(expect == result, "wrong return result from max_element");
+        EXPECT_TRUE(expect == result_pred, "wrong return result from max_element");
+    }
+};
+
+struct check_minmaxelement
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator begin, Iterator end)
+    {
+        typedef typename std::iterator_traits<Iterator>::value_type T;
+        const std::pair<Iterator, Iterator> expect = std::minmax_element(begin, end);
+        const std::pair<Iterator, Iterator> got = std::minmax_element(exec, begin, end);
+        const std::pair<Iterator, Iterator> got_pred = std::minmax_element(exec, begin, end, std::less<T>());
+        EXPECT_TRUE(expect.first == got.first, "wrong return result from minmax_element (min part)");
+        EXPECT_TRUE(expect.second == got.second, "wrong return result from minmax_element (max part)");
+        EXPECT_TRUE(expect == got_pred, "wrong return result from minmax_element");
+    }
+};
+
+template <typename T>
+struct sequence_wrapper
+{
+    TestUtils::Sequence<T> seq;
+    const T min_value;
+    const T max_value;
+    static const std::size_t bits = 30; // We assume that T can handle signed 2^bits+1 value
+
+    // TestUtils::HashBits returns value between 0 and (1<<bits)-1,
+    // therefore we could threat 1<<bits as maximum and -(1<<bits) as a minimum
+    sequence_wrapper(std::size_t n) : seq(n), min_value(-(1 << bits)), max_value(1 << bits) {}
+
+    void
+    pattern_fill()
+    {
+        seq.fill([](std::size_t i) -> T { return T(TestUtils::HashBits(i, bits)); });
+    }
+
+    // sets first one at position `at` and bunch of them farther
+    void
+    set_desired_value(std::size_t at, T value)
+    {
+        if (seq.size() == 0)
+            return;
+        seq[at] = value;
+
+        //Producing serveral red herrings
+        for (std::size_t i = at + 1; i < seq.size(); i += 1 + TestUtils::HashBits(i, 5))
+            seq[i] = value;
+    }
+};
+
+template <typename T>
+void
+test_by_type(std::size_t n)
+{
+    sequence_wrapper<T> wseq(n);
+
+    // to avoid overtesing we use std::set to leave only unique indexes
+    std::set<std::size_t> targets{0};
+    if (n > 1)
+    {
+        targets.insert(1);
+        targets.insert(2.718282 * n / 3);
+        targets.insert(n / 2);
+        targets.insert(n / 7.389056);
+        targets.insert(n - 1); // last
+    }
+
+    for (std::set<std::size_t>::iterator it = targets.begin(); it != targets.end(); ++it)
+    {
+        wseq.pattern_fill();
+        wseq.set_desired_value(*it, wseq.min_value);
+        TestUtils::invoke_on_all_policies(check_minelement(), wseq.seq.cbegin(), wseq.seq.cend());
+        TestUtils::invoke_on_all_policies(check_minelement(), wseq.seq.begin(), wseq.seq.end());
+
+        wseq.set_desired_value(*it, wseq.max_value);
+        TestUtils::invoke_on_all_policies(check_maxelement(), wseq.seq.cbegin(), wseq.seq.cend());
+        TestUtils::invoke_on_all_policies(check_maxelement(), wseq.seq.begin(), wseq.seq.end());
+
+        if (targets.size() > 1)
+        {
+            for (std::set<std::size_t>::reverse_iterator rit = targets.rbegin(); rit != targets.rend(); ++rit)
+            {
+                if (*rit == *it) // we requires at least 2 unique indexes in targets
+                    break;
+                wseq.pattern_fill();
+                wseq.set_desired_value(*it, wseq.min_value);  // setting minimum element
+                wseq.set_desired_value(*rit, wseq.max_value); // setting maximum element
+                TestUtils::invoke_on_all_policies(check_minmaxelement(), wseq.seq.cbegin(), wseq.seq.cend());
+                TestUtils::invoke_on_all_policies(check_minmaxelement(), wseq.seq.begin(), wseq.seq.end());
+            }
+        }
+        else
+        { // we must check this corner case; it can not be tested in loop above
+            TestUtils::invoke_on_all_policies(check_minmaxelement(), wseq.seq.cbegin(), wseq.seq.cend());
+            TestUtils::invoke_on_all_policies(check_minmaxelement(), wseq.seq.begin(), wseq.seq.end());
+        }
+    }
+}
+
+// should provide minimal requirements only
+struct OnlyLessCompare
+{
+    int32_t val;
+    OnlyLessCompare() : val(0) {}
+    OnlyLessCompare(int32_t val_) : val(val_) {}
+    bool
+    operator<(const OnlyLessCompare& other) const
+    {
+        return val < other.val;
+    }
+};
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator iter)
+    {
+        max_element(exec, iter, iter, non_const(std::less<T>()));
+        min_element(exec, iter, iter, non_const(std::less<T>()));
+        minmax_element(exec, iter, iter, non_const(std::less<T>()));
+    }
+};
+
+int
+main()
+{
+    using TestUtils::float64_t;
+    const std::size_t N = 100000;
+
+    for (std::size_t n = 0; n < N; n = n < 16 ? n + 1 : size_t(3.14159 * n))
+    {
+        test_by_type<float64_t>(n);
+        test_by_type<OnlyLessCompare>(n);
+    }
+
+    test_algo_basic_single<int32_t>(run_for_rnd_fw<test_non_const<int32_t>>());
+
+    std::cout << TestUtils::done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.sorting/alg.set.operations/includes.pass.cpp b/pstl/test/std/algorithms/alg.sorting/alg.set.operations/includes.pass.cpp
new file mode 100644
index 0000000..778d265
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.sorting/alg.set.operations/includes.pass.cpp
@@ -0,0 +1,106 @@
+// -*- C++ -*-
+//===-- includes.pass.cpp -------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <algorithm>
+#include <cmath>
+#include <execution>
+#include <functional>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+template <typename T>
+struct Num
+{
+    T val;
+    explicit Num(const T& v) : val(v) {}
+
+    //for "includes" checks
+    template <typename T1>
+    bool
+    operator<(const Num<T1>& v1) const
+    {
+        return val < v1.val;
+    }
+
+    //The types Type1 and Type2 must be such that an object of type InputIt can be dereferenced and then implicitly converted to both of them
+    template <typename T1>
+    operator Num<T1>() const
+    {
+        return Num<T1>((T1)val);
+    }
+};
+
+struct test_one_policy
+{
+    template <typename Policy, typename InputIterator1, typename InputIterator2, typename Compare>
+    typename std::enable_if<!TestUtils::isReverse<InputIterator1>::value, void>::type
+    operator()(Policy&& exec, InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2,
+               Compare comp)
+    {
+
+        auto expect_res = std::includes(first1, last1, first2, last2, comp);
+        auto res = std::includes(exec, first1, last1, first2, last2, comp);
+
+        EXPECT_TRUE(expect_res == res, "wrong result for includes");
+    }
+
+    template <typename Policy, typename InputIterator1, typename InputIterator2, typename Compare>
+    typename std::enable_if<TestUtils::isReverse<InputIterator1>::value, void>::type
+    operator()(Policy&&, InputIterator1, InputIterator1, InputIterator2, InputIterator2, Compare)
+    {
+    }
+};
+
+template <typename T1, typename T2, typename Compare>
+void
+test_includes(Compare compare)
+{
+
+    const std::size_t n_max = 1000000;
+
+    // The rand()%(2*n+1) encourages generation of some duplicates.
+    std::srand(42);
+
+    for (std::size_t n = 0; n < n_max; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        for (std::size_t m = 0; m < n_max; m = m <= 16 ? m + 1 : size_t(2.71828 * m))
+        {
+            //prepare the input ranges
+            Sequence<T1> in1(n, [](std::size_t k) { return rand() % (2 * k + 1); });
+            Sequence<T2> in2(m, [](std::size_t k) { return rand() % (k + 1); });
+
+            std::sort(in1.begin(), in1.end(), compare);
+            std::sort(in2.begin(), in2.end(), compare);
+
+            invoke_on_all_policies(test_one_policy(), in1.begin(), in1.end(), in2.cbegin(), in2.cend(), compare);
+
+            //test w/ non constant predicate
+            if (n < 5 && m < 5)
+                invoke_on_all_policies(test_one_policy(), in1.begin(), in1.end(), in2.cbegin(), in2.cend(),
+                                       non_const(compare));
+        }
+    }
+}
+
+int
+main()
+{
+
+    test_includes<float64_t, float64_t>(std::less<>());
+    test_includes<Num<int64_t>, Num<int32_t>>([](const Num<int64_t>& x, const Num<int32_t>& y) { return x < y; });
+    std::cout << done() << std::endl;
+
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.sorting/alg.set.operations/set.pass.cpp b/pstl/test/std/algorithms/alg.sorting/alg.set.operations/set.pass.cpp
new file mode 100644
index 0000000..40ae3d9
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.sorting/alg.set.operations/set.pass.cpp
@@ -0,0 +1,280 @@
+// -*- C++ -*-
+//===-- set.pass.cpp ------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <algorithm>
+#include <chrono>
+#include <cmath>
+#include <execution>
+#include <functional>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+template <typename T>
+struct Num
+{
+    T val;
+
+    Num() : val{} {}
+    Num(const T& v) : val(v) {}
+
+    //for "includes" checks
+    template <typename T1>
+    bool
+    operator<(const Num<T1>& v1) const
+    {
+        return val < v1.val;
+    }
+
+    //The types Type1 and Type2 must be such that an object of type InputIt can be dereferenced and then implicitly converted to both of them
+    template <typename T1>
+    operator Num<T1>() const
+    {
+        return Num<T1>((T1)val);
+    }
+
+    friend bool
+    operator==(const Num& v1, const Num& v2)
+    {
+        return v1.val == v2.val;
+    }
+};
+
+template <typename Type>
+struct test_set_union
+{
+    template <typename Policy, typename InputIterator1, typename InputIterator2, typename Compare>
+    typename std::enable_if<!TestUtils::isReverse<InputIterator1>::value, void>::type
+    operator()(Policy&& exec, InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2,
+               Compare comp)
+    {
+        using T1 = typename std::iterator_traits<InputIterator1>::value_type;
+
+        auto n1 = std::distance(first1, last1);
+        auto n2 = std::distance(first2, last2);
+        auto n = n1 + n2;
+        Sequence<T1> expect(n);
+        Sequence<T1> out(n);
+
+        auto expect_res = std::set_union(first1, last1, first2, last2, expect.begin(), comp);
+        auto res = std::set_union(exec, first1, last1, first2, last2, out.begin(), comp);
+
+        EXPECT_TRUE(expect_res - expect.begin() == res - out.begin(), "wrong result for set_union");
+        EXPECT_EQ_N(expect.begin(), out.begin(), std::distance(out.begin(), res), "wrong set_union effect");
+    }
+
+    template <typename Policy, typename InputIterator1, typename InputIterator2, typename Compare>
+    typename std::enable_if<TestUtils::isReverse<InputIterator1>::value, void>::type
+    operator()(Policy&&, InputIterator1, InputIterator1, InputIterator2, InputIterator2, Compare)
+    {
+    }
+};
+
+template <typename Type>
+struct test_set_intersection
+{
+    template <typename Policy, typename InputIterator1, typename InputIterator2, typename Compare>
+    typename std::enable_if<!TestUtils::isReverse<InputIterator1>::value, void>::type
+    operator()(Policy&& exec, InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2,
+               Compare comp)
+    {
+        using T1 = typename std::iterator_traits<InputIterator1>::value_type;
+
+        auto n1 = std::distance(first1, last1);
+        auto n2 = std::distance(first2, last2);
+        auto n = n1 + n2;
+        Sequence<T1> expect(n);
+        Sequence<T1> out(n);
+
+        auto expect_res = std::set_intersection(first1, last1, first2, last2, expect.begin(), comp);
+        auto res = std::set_intersection(exec, first1, last1, first2, last2, out.begin(), comp);
+
+        EXPECT_TRUE(expect_res - expect.begin() == res - out.begin(), "wrong result for set_intersection");
+        EXPECT_EQ_N(expect.begin(), out.begin(), std::distance(out.begin(), res), "wrong set_intersection effect");
+    }
+
+    template <typename Policy, typename InputIterator1, typename InputIterator2, typename Compare>
+    typename std::enable_if<TestUtils::isReverse<InputIterator1>::value, void>::type
+    operator()(Policy&&, InputIterator1, InputIterator1, InputIterator2, InputIterator2, Compare)
+    {
+    }
+};
+
+template <typename Type>
+struct test_set_difference
+{
+    template <typename Policy, typename InputIterator1, typename InputIterator2, typename Compare>
+    typename std::enable_if<!TestUtils::isReverse<InputIterator1>::value, void>::type
+    operator()(Policy&& exec, InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2,
+               Compare comp)
+    {
+        using T1 = typename std::iterator_traits<InputIterator1>::value_type;
+
+        auto n1 = std::distance(first1, last1);
+        auto n2 = std::distance(first2, last2);
+        auto n = n1 + n2;
+        Sequence<T1> expect(n);
+        Sequence<T1> out(n);
+
+        auto expect_res = std::set_difference(first1, last1, first2, last2, expect.begin(), comp);
+        auto res = std::set_difference(exec, first1, last1, first2, last2, out.begin(), comp);
+
+        EXPECT_TRUE(expect_res - expect.begin() == res - out.begin(), "wrong result for set_difference");
+        EXPECT_EQ_N(expect.begin(), out.begin(), std::distance(out.begin(), res), "wrong set_difference effect");
+    }
+
+    template <typename Policy, typename InputIterator1, typename InputIterator2, typename Compare>
+    typename std::enable_if<TestUtils::isReverse<InputIterator1>::value, void>::type
+    operator()(Policy&&, InputIterator1, InputIterator1, InputIterator2, InputIterator2, Compare)
+    {
+    }
+};
+
+template <typename Type>
+struct test_set_symmetric_difference
+{
+    template <typename Policy, typename InputIterator1, typename InputIterator2, typename Compare>
+    typename std::enable_if<!TestUtils::isReverse<InputIterator1>::value, void>::type
+    operator()(Policy&& exec, InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2,
+               Compare comp)
+    {
+        using T1 = typename std::iterator_traits<InputIterator1>::value_type;
+
+        auto n1 = std::distance(first1, last1);
+        auto n2 = std::distance(first2, last2);
+        auto n = n1 + n2;
+        Sequence<T1> expect(n);
+        Sequence<T1> out(n);
+
+        auto expect_res = std::set_symmetric_difference(first1, last1, first2, last2, expect.begin(), comp);
+        auto res = std::set_symmetric_difference(exec, first1, last1, first2, last2, out.begin(), comp);
+
+        EXPECT_TRUE(expect_res - expect.begin() == res - out.begin(), "wrong result for set_symmetric_difference");
+        EXPECT_EQ_N(expect.begin(), out.begin(), std::distance(out.begin(), res),
+                    "wrong set_symmetric_difference effect");
+    }
+
+    template <typename Policy, typename InputIterator1, typename InputIterator2, typename Compare>
+    typename std::enable_if<TestUtils::isReverse<InputIterator1>::value, void>::type
+    operator()(Policy&&, InputIterator1, InputIterator1, InputIterator2, InputIterator2, Compare)
+    {
+    }
+};
+
+template <typename T1, typename T2, typename Compare>
+void
+test_set(Compare compare)
+{
+
+    const std::size_t n_max = 100000;
+
+    // The rand()%(2*n+1) encourages generation of some duplicates.
+    std::srand(4200);
+
+    for (std::size_t n = 0; n < n_max; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        for (std::size_t m = 0; m < n_max; m = m <= 16 ? m + 1 : size_t(2.71828 * m))
+        {
+            //prepare the input ranges
+            Sequence<T1> in1(n, [](std::size_t k) { return rand() % (2 * k + 1); });
+            Sequence<T2> in2(m, [m](std::size_t k) { return (m % 2) * rand() + rand() % (k + 1); });
+
+            std::sort(in1.begin(), in1.end(), compare);
+            std::sort(in2.begin(), in2.end(), compare);
+
+            invoke_on_all_policies(test_set_union<T1>(), in1.begin(), in1.end(), in2.cbegin(), in2.cend(),
+                                        compare);
+
+            invoke_on_all_policies(test_set_intersection<T1>(), in1.begin(), in1.end(), in2.cbegin(), in2.cend(),
+                                        compare);
+
+            invoke_on_all_policies(test_set_difference<T1>(), in1.begin(), in1.end(), in2.cbegin(), in2.cend(),
+                                        compare);
+
+            invoke_on_all_policies(test_set_symmetric_difference<T1>(), in1.begin(), in1.end(), in2.cbegin(),
+                                        in2.cend(), compare);
+        }
+    }
+}
+
+template <typename T>
+struct test_non_const_set_difference
+{
+    template <typename Policy, typename InputIterator, typename OutputInterator>
+    void
+    operator()(Policy&& exec, InputIterator input_iter, OutputInterator out_iter)
+    {
+        set_difference(exec, input_iter, input_iter, input_iter, input_iter, out_iter, non_const(std::less<T>()));
+    }
+};
+
+template <typename T>
+struct test_non_const_set_intersection
+{
+    template <typename Policy, typename InputIterator, typename OutputInterator>
+    void
+    operator()(Policy&& exec, InputIterator input_iter, OutputInterator out_iter)
+    {
+        set_intersection(exec, input_iter, input_iter, input_iter, input_iter, out_iter, non_const(std::less<T>()));
+    }
+};
+
+template <typename T>
+struct test_non_const_set_symmetric_difference
+{
+    template <typename Policy, typename InputIterator, typename OutputInterator>
+    void
+    operator()(Policy&& exec, InputIterator input_iter, OutputInterator out_iter)
+    {
+        set_symmetric_difference(exec, input_iter, input_iter, input_iter, input_iter, out_iter,
+                                 non_const(std::less<T>()));
+    }
+};
+
+template <typename T>
+struct test_non_const_set_union
+{
+    template <typename Policy, typename InputIterator, typename OutputInterator>
+    void
+    operator()(Policy&& exec, InputIterator input_iter, OutputInterator out_iter)
+    {
+        set_union(exec, input_iter, input_iter, input_iter, input_iter, out_iter, non_const(std::less<T>()));
+    }
+};
+
+int
+main()
+{
+
+    test_set<float64_t, float64_t>(std::less<>());
+    test_set<Num<int64_t>, Num<int32_t>>([](const Num<int64_t>& x, const Num<int32_t>& y) { return x < y; });
+
+    test_set<MemoryChecker, MemoryChecker>([](const MemoryChecker& val1, const MemoryChecker& val2) -> bool {
+        return val1.value() < val2.value();
+    });
+    EXPECT_FALSE(MemoryChecker::alive_objects() < 0, "wrong effect from set algorithms: number of ctors calls < num of dtors calls");
+    EXPECT_FALSE(MemoryChecker::alive_objects() > 0, "wrong effect from set algorithms: number of ctors calls > num of dtors calls");
+
+    test_algo_basic_double<int32_t>(run_for_rnd_fw<test_non_const_set_difference<int32_t>>());
+
+    test_algo_basic_double<int32_t>(run_for_rnd_fw<test_non_const_set_intersection<int32_t>>());
+
+    test_algo_basic_double<int32_t>(run_for_rnd_fw<test_non_const_set_symmetric_difference<int32_t>>());
+
+    test_algo_basic_double<int32_t>(run_for_rnd_fw<test_non_const_set_union<int32_t>>());
+
+    std::cout << done() << std::endl;
+
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.sorting/is_sorted.pass.cpp b/pstl/test/std/algorithms/alg.sorting/is_sorted.pass.cpp
new file mode 100644
index 0000000..d4c6fe2
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.sorting/is_sorted.pass.cpp
@@ -0,0 +1,100 @@
+// -*- C++ -*-
+//===-- is_sorted.pass.cpp ------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct test_is_sorted
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator first, Iterator last, bool exam)
+    {
+        using namespace std;
+        typedef typename std::iterator_traits<Iterator>::value_type T;
+
+        //try random-access iterator
+        bool res = is_sorted(exec, first, last);
+        EXPECT_TRUE(exam == res, "is_sorted wrong result for random-access iterator");
+        auto iexam = is_sorted_until(first, last);
+        auto ires = is_sorted_until(exec, first, last);
+        EXPECT_TRUE(iexam == ires, "is_sorted_until wrong result for random-access iterator");
+
+        //try random-access iterator with a predicate
+        res = is_sorted(exec, first, last, std::less<T>());
+        EXPECT_TRUE(exam == res, "is_sorted wrong result for random-access iterator");
+        iexam = is_sorted_until(first, last, std::less<T>());
+        ires = is_sorted_until(exec, first, last, std::less<T>());
+        EXPECT_TRUE(iexam == ires, "is_sorted_until wrong result for random-access iterator");
+    }
+};
+
+template <typename T>
+void
+test_is_sorted_by_type()
+{
+
+    Sequence<T> in(99999, [](size_t v) -> T { return T(v); }); //fill 0..n
+
+    invoke_on_all_policies(test_is_sorted(), in.begin(), in.end(), std::is_sorted(in.begin(), in.end()));
+    invoke_on_all_policies(test_is_sorted(), in.cbegin(), in.cend(), std::is_sorted(in.begin(), in.end()));
+
+    in[in.size() / 2] = -1;
+    invoke_on_all_policies(test_is_sorted(), in.begin(), in.end(), std::is_sorted(in.begin(), in.end()));
+    invoke_on_all_policies(test_is_sorted(), in.cbegin(), in.cend(), std::is_sorted(in.begin(), in.end()));
+
+    in[1] = -1;
+    invoke_on_all_policies(test_is_sorted(), in.begin(), in.end(), std::is_sorted(in.begin(), in.end()));
+    invoke_on_all_policies(test_is_sorted(), in.cbegin(), in.cend(), std::is_sorted(in.begin(), in.end()));
+
+    //an empty container
+    Sequence<T> in0(0);
+    invoke_on_all_policies(test_is_sorted(), in0.begin(), in0.end(), std::is_sorted(in0.begin(), in0.end()));
+    invoke_on_all_policies(test_is_sorted(), in0.cbegin(), in0.cend(), std::is_sorted(in0.begin(), in0.end()));
+
+    //non-descending order
+    Sequence<T> in1(9, [](size_t) -> T { return T(0); });
+    invoke_on_all_policies(test_is_sorted(), in1.begin(), in1.end(), std::is_sorted(in1.begin(), in1.end()));
+    invoke_on_all_policies(test_is_sorted(), in1.cbegin(), in1.cend(), std::is_sorted(in1.begin(), in1.end()));
+}
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator iter)
+    {
+        is_sorted(exec, iter, iter, std::less<T>());
+        is_sorted_until(exec, iter, iter, std::less<T>());
+    }
+};
+
+int
+main()
+{
+
+    test_is_sorted_by_type<int32_t>();
+    test_is_sorted_by_type<float64_t>();
+
+    test_is_sorted_by_type<Wrapper<int32_t>>();
+
+    test_algo_basic_single<int32_t>(run_for_rnd_fw<test_non_const<int32_t>>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.sorting/partial_sort.pass.cpp b/pstl/test/std/algorithms/alg.sorting/partial_sort.pass.cpp
new file mode 100644
index 0000000..bf6e68b
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.sorting/partial_sort.pass.cpp
@@ -0,0 +1,149 @@
+// -*- C++ -*-
+//===-- partial_sort.pass.cpp ---------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <cmath>
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+static std::atomic<int32_t> count_val;
+static std::atomic<int32_t> count_comp;
+
+template <typename T>
+struct Num
+{
+    T val;
+
+    Num() { ++count_val; }
+    Num(T v) : val(v) { ++count_val; }
+    Num(const Num<T>& v) : val(v.val) { ++count_val; }
+    Num(Num<T>&& v) : val(v.val) { ++count_val; }
+    ~Num() { --count_val; }
+    Num<T>&
+    operator=(const Num<T>& v)
+    {
+        val = v.val;
+        return *this;
+    }
+    operator T() const { return val; }
+    bool
+    operator<(const Num<T>& v) const
+    {
+        ++count_comp;
+        return val < v.val;
+    }
+};
+
+struct test_brick_partial_sort
+{
+    template <typename Policy, typename InputIterator, typename Compare>
+    typename std::enable_if<is_same_iterator_category<InputIterator, std::random_access_iterator_tag>::value,
+                            void>::type
+    operator()(Policy&& exec, InputIterator first, InputIterator last, InputIterator exp_first, InputIterator exp_last,
+               Compare compare)
+    {
+
+        typedef typename std::iterator_traits<InputIterator>::value_type T;
+
+        // The rand()%(2*n+1) encourages generation of some duplicates.
+        std::srand(42);
+        const std::size_t n = last - first;
+        for (std::size_t k = 0; k < n; ++k)
+        {
+            first[k] = T(rand() % (2 * n + 1));
+        }
+        std::copy(first, last, exp_first);
+
+        for (std::size_t p = 0; p < n; p = p <= 16 ? p + 1 : std::size_t(31.415 * p))
+        {
+            auto m1 = first + p;
+            auto m2 = exp_first + p;
+
+            std::partial_sort(exp_first, m2, exp_last, compare);
+            count_comp = 0;
+            std::partial_sort(exec, first, m1, last, compare);
+            EXPECT_EQ_N(exp_first, first, p, "wrong effect from partial_sort");
+
+            //checking upper bound number of comparisons; O(p*(last-first)log(middle-first)); where p - number of threads;
+            if (m1 - first > 1)
+            {
+#ifdef _DEBUG
+#    if defined(_PSTL_PAR_BACKEND_TBB)
+                auto p = tbb::this_task_arena::max_concurrency();
+#    else
+                auto p = 1;
+#    endif
+                auto complex = std::ceil(n * std::log(float32_t(m1 - first)));
+                if (count_comp > complex * p)
+                {
+                    std::cout << "complexity exceeded" << std::endl;
+                }
+#endif // _DEBUG
+            }
+        }
+    }
+
+    template <typename Policy, typename InputIterator, typename Compare>
+    typename std::enable_if<!is_same_iterator_category<InputIterator, std::random_access_iterator_tag>::value,
+                            void>::type
+    operator()(Policy&&, InputIterator, InputIterator, InputIterator, InputIterator, Compare)
+    {
+    }
+};
+
+template <typename T, typename Compare>
+void
+test_partial_sort(Compare compare)
+{
+
+    const std::size_t n_max = 100000;
+    Sequence<T> in(n_max);
+    Sequence<T> exp(n_max);
+    for (std::size_t n = 0; n < n_max; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        invoke_on_all_policies(test_brick_partial_sort(), in.begin(), in.begin() + n, exp.begin(), exp.begin() + n,
+                               compare);
+    }
+}
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator iter)
+    {
+        partial_sort(exec, iter, iter, iter, non_const(std::less<T>()));
+    }
+};
+
+int
+main()
+{
+    count_val = 0;
+
+    test_partial_sort<Num<float32_t>>([](Num<float32_t> x, Num<float32_t> y) { return x < y; });
+
+    EXPECT_TRUE(count_val == 0, "cleanup error");
+
+    test_partial_sort<int32_t>(
+        [](int32_t x, int32_t y) { return x > y; }); // Reversed so accidental use of < will be detected.
+
+    test_algo_basic_single<int32_t>(run_for_rnd<test_non_const<int32_t>>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.sorting/partial_sort_copy.pass.cpp b/pstl/test/std/algorithms/alg.sorting/partial_sort_copy.pass.cpp
new file mode 100644
index 0000000..9090f89
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.sorting/partial_sort_copy.pass.cpp
@@ -0,0 +1,196 @@
+// -*- C++ -*-
+//===-- partial_sort_copy.pass.cpp ----------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+// Tests for partial_sort_copy
+#include "support/pstl_test_config.h"
+
+#include <cmath>
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+template <typename T>
+struct Num
+{
+    T val;
+
+    Num() : val(0) {}
+    Num(T v) : val(v) {}
+    Num(const Num<T>& v) : val(v.val) {}
+    Num(Num<T>&& v) : val(v.val) {}
+    Num<T>&
+    operator=(const Num<T>& v)
+    {
+        val = v.val;
+        return *this;
+    }
+    operator T() const { return val; }
+    bool
+    operator<(const Num<T>& v) const
+    {
+        return val < v.val;
+    }
+};
+
+template <typename RandomAccessIterator>
+struct test_one_policy
+{
+    RandomAccessIterator d_first;
+    RandomAccessIterator d_last;
+    RandomAccessIterator exp_first;
+    RandomAccessIterator exp_last;
+    // This ctor is needed because output shouldn't be transformed to any iterator type (only random access iterators are allowed)
+    test_one_policy(RandomAccessIterator b1, RandomAccessIterator e1, RandomAccessIterator b2, RandomAccessIterator e2)
+        : d_first(b1), d_last(e1), exp_first(b2), exp_last(e2)
+    {
+    }
+#if defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) ||                                                             \
+    defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) // dummy specialization by policy type, in case of broken configuration
+    template <typename InputIterator, typename Size, typename T, typename Compare>
+    void
+    operator()(pstl::execution::unsequenced_policy, InputIterator first, InputIterator last, Size n1, Size n2,
+               const T& trash, Compare compare)
+    {
+    }
+
+    template <typename InputIterator, typename Size, typename T, typename Compare>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, InputIterator first, InputIterator last, Size n1, Size n2,
+               const T& trash, Compare compare)
+    {
+    }
+
+    template <typename InputIterator, typename Size, typename T>
+    void
+    operator()(pstl::execution::unsequenced_policy, InputIterator first, InputIterator last, Size n1, Size n2,
+               const T& trash)
+    {
+    }
+
+    template <typename InputIterator, typename Size, typename T>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, InputIterator first, InputIterator last, Size n1, Size n2,
+               const T& trash)
+    {
+    }
+#endif
+
+    template <typename Policy, typename InputIterator, typename Size, typename T, typename Compare>
+    void
+    operator()(Policy&& exec, InputIterator first, InputIterator last, Size n1, Size n2, const T& trash,
+               Compare compare)
+    {
+        prepare_data(first, last, n1, trash);
+        RandomAccessIterator exp = std::partial_sort_copy(first, last, exp_first, exp_last, compare);
+        RandomAccessIterator res = std::partial_sort_copy(exec, first, last, d_first, d_last, compare);
+
+        EXPECT_TRUE((exp - exp_first) == (res - d_first), "wrong result from partial_sort_copy with predicate");
+        EXPECT_EQ_N(exp_first, d_first, n2, "wrong effect from partial_sort_copy with predicate");
+    }
+
+    template <typename Policy, typename InputIterator, typename Size, typename T>
+    void
+    operator()(Policy&& exec, InputIterator first, InputIterator last, Size n1, Size n2, const T& trash)
+    {
+        prepare_data(first, last, n1, trash);
+        RandomAccessIterator exp = std::partial_sort_copy(first, last, exp_first, exp_last);
+        RandomAccessIterator res = std::partial_sort_copy(exec, first, last, d_first, d_last);
+
+        EXPECT_TRUE((exp - exp_first) == (res - d_first), "wrong result from partial_sort_copy without predicate");
+        EXPECT_EQ_N(exp_first, d_first, n2, "wrong effect from partial_sort_copy without predicate");
+    }
+
+  private:
+    template <typename InputIterator, typename Size, typename T>
+    void
+    prepare_data(InputIterator first, InputIterator last, Size n1, const T& trash)
+    {
+        // The rand()%(2*n+1) encourages generation of some duplicates.
+        std::srand(42);
+        std::generate(first, last, [n1]() { return T(rand() % (2 * n1 + 1)); });
+
+        std::fill(exp_first, exp_last, trash);
+        std::fill(d_first, d_last, trash);
+    }
+};
+
+template <typename T, typename Compare>
+void
+test_partial_sort_copy(Compare compare)
+{
+
+    typedef typename Sequence<T>::iterator iterator_type;
+    const std::size_t n_max = 100000;
+    Sequence<T> in(n_max);
+    Sequence<T> out(2 * n_max);
+    Sequence<T> exp(2 * n_max);
+    std::size_t n1 = 0;
+    std::size_t n2;
+    T trash = T(-666);
+    for (; n1 < n_max; n1 = n1 <= 16 ? n1 + 1 : size_t(3.1415 * n1))
+    {
+        // If both sequences are equal
+        n2 = n1;
+        invoke_on_all_policies(
+            test_one_policy<iterator_type>(out.begin(), out.begin() + n2, exp.begin(), exp.begin() + n2), in.begin(),
+            in.begin() + n1, n1, n2, trash, compare);
+
+        // If first sequence is greater than second
+        n2 = n1 / 3;
+        invoke_on_all_policies(
+            test_one_policy<iterator_type>(out.begin(), out.begin() + n2, exp.begin(), exp.begin() + n2), in.begin(),
+            in.begin() + n1, n1, n2, trash, compare);
+
+        // If first sequence is less than second
+        n2 = 2 * n1;
+        invoke_on_all_policies(
+            test_one_policy<iterator_type>(out.begin(), out.begin() + n2, exp.begin(), exp.begin() + n2), in.begin(),
+            in.begin() + n1, n1, n2, trash, compare);
+    }
+    // Test partial_sort_copy without predicate
+    n1 = n_max;
+    n2 = 2 * n1;
+    invoke_on_all_policies(test_one_policy<iterator_type>(out.begin(), out.begin() + n2, exp.begin(), exp.begin() + n2),
+                           in.begin(), in.begin() + n1, n1, n2, trash);
+}
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename InputIterator, typename OutputInterator>
+    void
+    operator()(Policy&& exec, InputIterator input_iter, OutputInterator out_iter)
+    {
+        invoke_if(exec, [&]() {
+            partial_sort_copy(exec, input_iter, input_iter, out_iter, out_iter, non_const(std::less<T>()));
+        });
+    }
+};
+
+int
+main()
+{
+    test_partial_sort_copy<Num<float32_t>>([](Num<float32_t> x, Num<float32_t> y) { return x < y; });
+    test_partial_sort_copy<int32_t>([](int32_t x, int32_t y) { return x > y; });
+
+    test_algo_basic_double<int32_t>(run_for_rnd<test_non_const<int32_t>>());
+
+    test_partial_sort_copy<MemoryChecker>(
+        [](const MemoryChecker& val1, const MemoryChecker& val2){ return val1.value() < val2.value(); });
+    EXPECT_FALSE(MemoryChecker::alive_objects() < 0, "wrong effect from partial_sort_copy: number of ctors calls < num of dtors calls");
+    EXPECT_FALSE(MemoryChecker::alive_objects() > 0, "wrong effect from partial_sort_copy: number of ctors calls > num of dtors calls");
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/algorithms/alg.sorting/sort.pass.cpp b/pstl/test/std/algorithms/alg.sorting/sort.pass.cpp
new file mode 100644
index 0000000..5617a60
--- /dev/null
+++ b/pstl/test/std/algorithms/alg.sorting/sort.pass.cpp
@@ -0,0 +1,247 @@
+// -*- C++ -*-
+//===-- sort.pass.cpp -----------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <algorithm>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+#define _CRT_SECURE_NO_WARNINGS
+
+#include <atomic>
+
+static bool Stable;
+
+//! Number of extant keys
+static std::atomic<int32_t> KeyCount;
+
+//! One more than highest index in array to be sorted.
+static uint32_t LastIndex;
+
+//! Keeping Equal() static and a friend of ParanoidKey class (C++, paragraphs 3.5/7.1.1)
+class ParanoidKey;
+static bool
+Equal(const ParanoidKey& x, const ParanoidKey& y);
+
+//! A key to be sorted, with lots of checking.
+class ParanoidKey
+{
+    //! Value used by comparator
+    int32_t value;
+    //! Original position or special value (Empty or Dead)
+    int32_t index;
+    //! Special value used to mark object without a comparable value, e.g. after being moved from.
+    static const int32_t Empty = -1;
+    //! Special value used to mark destroyed objects.
+    static const int32_t Dead = -2;
+    // True if key object has comparable value
+    bool
+    isLive() const
+    {
+        return (uint32_t)(index) < LastIndex;
+    }
+    // True if key object has been constructed.
+    bool
+    isConstructed() const
+    {
+        return isLive() || index == Empty;
+    }
+
+  public:
+    ParanoidKey()
+    {
+        ++KeyCount;
+        index = Empty;
+        value = Empty;
+    }
+    ParanoidKey(const ParanoidKey& k) : value(k.value), index(k.index)
+    {
+        EXPECT_TRUE(k.isLive(), "source for copy-constructor is dead");
+        ++KeyCount;
+    }
+    ~ParanoidKey()
+    {
+        EXPECT_TRUE(isConstructed(), "double destruction");
+        index = Dead;
+        --KeyCount;
+    }
+    ParanoidKey&
+    operator=(const ParanoidKey& k)
+    {
+        EXPECT_TRUE(k.isLive(), "source for copy-assignment is dead");
+        EXPECT_TRUE(isConstructed(), "destination for copy-assignment is dead");
+        value = k.value;
+        index = k.index;
+        return *this;
+    }
+    ParanoidKey(int32_t index, int32_t value, OddTag) : value(value), index(index) {}
+    ParanoidKey(ParanoidKey&& k) : value(k.value), index(k.index)
+    {
+        EXPECT_TRUE(k.isConstructed(), "source for move-construction is dead");
+// std::stable_sort() fails in move semantics on paranoid test before VS2015
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
+        k.index = Empty;
+#endif
+        ++KeyCount;
+    }
+    ParanoidKey&
+    operator=(ParanoidKey&& k)
+    {
+        EXPECT_TRUE(k.isConstructed(), "source for move-assignment is dead");
+        EXPECT_TRUE(isConstructed(), "destination for move-assignment is dead");
+        value = k.value;
+        index = k.index;
+// std::stable_sort() fails in move semantics on paranoid test before VS2015
+#if !defined(_MSC_VER) || _MSC_VER >= 1900
+        k.index = Empty;
+#endif
+        return *this;
+    }
+    friend class KeyCompare;
+    friend bool
+    Equal(const ParanoidKey& x, const ParanoidKey& y);
+};
+
+class KeyCompare
+{
+    enum statusType
+    {
+        //! Special value used to mark defined object.
+        Live = 0xabcd,
+        //! Special value used to mark destroyed objects.
+        Dead = -1
+    } status;
+
+  public:
+    KeyCompare(OddTag) : status(Live) {}
+    ~KeyCompare() { status = Dead; }
+    bool
+    operator()(const ParanoidKey& j, const ParanoidKey& k) const
+    {
+        EXPECT_TRUE(status == Live, "key comparison object not defined");
+        EXPECT_TRUE(j.isLive(), "first key to operator() is not live");
+        EXPECT_TRUE(k.isLive(), "second key to operator() is not live");
+        return j.value < k.value;
+    }
+};
+
+// Equal is equality comparison used for checking result of sort against expected result.
+static bool
+Equal(const ParanoidKey& x, const ParanoidKey& y)
+{
+    return (x.value == y.value && !Stable) || (x.index == y.index);
+}
+
+static bool
+Equal(float32_t x, float32_t y)
+{
+    return x == y;
+}
+
+static bool
+Equal(int32_t x, int32_t y)
+{
+    return x == y;
+}
+
+struct test_sort_with_compare
+{
+    template <typename Policy, typename InputIterator, typename OutputIterator, typename OutputIterator2, typename Size,
+              typename Compare>
+    typename std::enable_if<is_same_iterator_category<InputIterator, std::random_access_iterator_tag>::value,
+                            void>::type
+    operator()(Policy&& exec, OutputIterator tmp_first, OutputIterator tmp_last, OutputIterator2 expected_first,
+               OutputIterator2 expected_last, InputIterator first, InputIterator, Size n, Compare compare)
+    {
+        using namespace std;
+        copy_n(first, n, expected_first);
+        copy_n(first, n, tmp_first);
+        if (Stable)
+            std::stable_sort(expected_first + 1, expected_last - 1, compare);
+        else
+            std::sort(expected_first + 1, expected_last - 1, compare);
+        int32_t count0 = KeyCount;
+        if (Stable)
+            stable_sort(exec, tmp_first + 1, tmp_last - 1, compare);
+        else
+            sort(exec, tmp_first + 1, tmp_last - 1, compare);
+
+        for (size_t i = 0; i < n; ++i, ++expected_first, ++tmp_first)
+        {
+            // Check that expected[i] is equal to tmp[i]
+            EXPECT_TRUE(Equal(*expected_first, *tmp_first), "bad sort");
+        }
+        int32_t count1 = KeyCount;
+        EXPECT_EQ(count0, count1, "key cleanup error");
+    }
+    template <typename Policy, typename InputIterator, typename OutputIterator, typename OutputIterator2, typename Size,
+              typename Compare>
+    typename std::enable_if<!is_same_iterator_category<InputIterator, std::random_access_iterator_tag>::value,
+                            void>::type
+    operator()(Policy&&, OutputIterator, OutputIterator, OutputIterator2, OutputIterator2, InputIterator, InputIterator,
+               Size, Compare)
+    {
+    }
+};
+
+template <typename T, typename Compare, typename Convert>
+void
+test_sort(Compare compare, Convert convert)
+{
+    for (size_t n = 0; n < 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        LastIndex = n + 2;
+        // The rand()%(2*n+1) encourages generation of some duplicates.
+        // Sequence is padded with an extra element at front and back, to detect overwrite bugs.
+        Sequence<T> in(n + 2, [=](size_t k) { return convert(k, rand() % (2 * n + 1)); });
+        Sequence<T> expected(in);
+        Sequence<T> tmp(in);
+        invoke_on_all_policies(test_sort_with_compare(), tmp.begin(), tmp.end(), expected.begin(), expected.end(),
+                               in.begin(), in.end(), in.size(), compare);
+    }
+}
+
+template <typename T>
+struct test_non_const
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator iter)
+    {
+        sort(exec, iter, iter, non_const(std::less<T>()));
+        stable_sort(exec, iter, iter, non_const(std::less<T>()));
+    }
+};
+
+int
+main()
+{
+    std::srand(42);
+    for (int32_t kind = 0; kind < 2; ++kind)
+    {
+        Stable = kind != 0;
+        test_sort<ParanoidKey>(KeyCompare(OddTag()),
+                               [](size_t k, size_t val) { return ParanoidKey(k, val, OddTag()); });
+        test_sort<float32_t>([](float32_t x, float32_t y) { return x < y; },
+                             [](size_t, size_t val) { return float32_t(val); });
+        test_sort<int32_t>(
+            [](int32_t x, int32_t y) { return x > y; }, // Reversed so accidental use of < will be detected.
+            [](size_t, size_t val) { return int32_t(val); });
+    }
+
+    test_algo_basic_single<int32_t>(run_for_rnd<test_non_const<int32_t>>());
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/lit.local.cfg b/pstl/test/std/lit.local.cfg
new file mode 100644
index 0000000..f259d8f
--- /dev/null
+++ b/pstl/test/std/lit.local.cfg
@@ -0,0 +1,2 @@
+if "parallel-algorithms" not in config.available_features:
+    config.unsupported = True
diff --git a/pstl/test/std/numerics/numeric.ops/adjacent_difference.pass.cpp b/pstl/test/std/numerics/numeric.ops/adjacent_difference.pass.cpp
new file mode 100644
index 0000000..8e56f61
--- /dev/null
+++ b/pstl/test/std/numerics/numeric.ops/adjacent_difference.pass.cpp
@@ -0,0 +1,170 @@
+// -*- C++ -*-
+//===-- adjacent_difference.pass.cpp --------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <iterator>
+#include <execution>
+#include <numeric>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+template <typename T>
+struct wrapper
+{
+    T t;
+    constexpr explicit wrapper(T t_) : t(t_) {}
+    template <typename T2>
+    constexpr wrapper(const wrapper<T2>& a)
+    {
+        t = a.t;
+    }
+    template <typename T2>
+    constexpr void
+    operator=(const wrapper<T2>& a)
+    {
+        t = a.t;
+    }
+    constexpr wrapper<T>
+    operator-(const wrapper<T>& a) const
+    {
+        return wrapper<T>(t - a.t);
+    }
+};
+
+template <typename T>
+bool
+compare(const T& a, const T& b)
+{
+    return a == b;
+}
+
+template <typename T>
+bool
+compare(const wrapper<T>& a, const wrapper<T>& b)
+{
+    return a.t == b.t;
+}
+
+template <typename Iterator1, typename Iterator2, typename T, typename Function>
+typename std::enable_if<!std::is_floating_point<T>::value, bool>::type
+compute_and_check(Iterator1 first, Iterator1 last, Iterator2 d_first, T, Function f)
+{
+    using T2 = typename std::iterator_traits<Iterator2>::value_type;
+
+    if (first == last)
+        return true;
+
+    {
+        T2 temp(*first);
+        if (!compare(temp, *d_first))
+            return false;
+    }
+    Iterator1 second = std::next(first);
+
+    ++d_first;
+    for (; second != last; ++first, ++second, ++d_first)
+    {
+        T2 temp(f(*second, *first));
+        if (!compare(temp, *d_first))
+            return false;
+    }
+
+    return true;
+}
+
+// we don't want to check equality here
+// because we can't be sure it will be strictly equal for floating point types
+template <typename Iterator1, typename Iterator2, typename T, typename Function>
+typename std::enable_if<std::is_floating_point<T>::value, bool>::type compute_and_check(Iterator1, Iterator1, Iterator2,
+                                                                                        T, Function)
+{
+    return true;
+}
+
+struct test_one_policy
+{
+#if defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) ||                                                             \
+    defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) // dummy specialization by policy type, in case of broken configuration
+    template <typename Iterator1, typename Iterator2, typename T, typename Function>
+    typename std::enable_if<is_same_iterator_category<Iterator1, std::random_access_iterator_tag>::value, void>::type
+    operator()(pstl::execution::unsequenced_policy, Iterator1 data_b, Iterator1 data_e, Iterator2 actual_b,
+               Iterator2 actual_e, T trash, Function f)
+    {
+    }
+    template <typename Iterator1, typename Iterator2, typename T, typename Function>
+    typename std::enable_if<is_same_iterator_category<Iterator1, std::random_access_iterator_tag>::value, void>::type
+    operator()(pstl::execution::parallel_unsequenced_policy, Iterator1 data_b, Iterator1 data_e, Iterator2 actual_b,
+               Iterator2 actual_e, T trash, Function f)
+    {
+    }
+#endif
+
+    template <typename ExecutionPolicy, typename Iterator1, typename Iterator2, typename T, typename Function>
+    void
+    operator()(ExecutionPolicy&& exec, Iterator1 data_b, Iterator1 data_e, Iterator2 actual_b, Iterator2 actual_e,
+               T trash, Function f)
+    {
+        using namespace std;
+        using T2 = typename std::iterator_traits<Iterator1>::value_type;
+
+        fill(actual_b, actual_e, trash);
+
+        Iterator2 actual_return = adjacent_difference(exec, data_b, data_e, actual_b);
+        EXPECT_TRUE(compute_and_check(data_b, data_e, actual_b, T2(0), std::minus<T2>()),
+                    "wrong effect of adjacent_difference");
+        EXPECT_TRUE(actual_return == actual_e, "wrong result of adjacent_difference");
+
+        fill(actual_b, actual_e, trash);
+
+        actual_return = adjacent_difference(exec, data_b, data_e, actual_b, f);
+        EXPECT_TRUE(compute_and_check(data_b, data_e, actual_b, T2(0), f),
+                    "wrong effect of adjacent_difference with functor");
+        EXPECT_TRUE(actual_return == actual_e, "wrong result of adjacent_difference with functor");
+    }
+};
+
+template <typename T1, typename T2, typename Pred>
+void
+test(Pred pred)
+{
+    const std::size_t max_len = 100000;
+
+    static constexpr T2 value = T2(77);
+    static constexpr T1 trash = T1(31);
+
+    Sequence<T1> actual(max_len, [](std::size_t i) { return T1(i); });
+
+    Sequence<T2> data(max_len, [](std::size_t i) { return i % 3 == 2 ? T2(i * i) : value; });
+
+    for (std::size_t len = 0; len < max_len; len = len <= 16 ? len + 1 : std::size_t(3.1415 * len))
+    {
+        invoke_on_all_policies(test_one_policy(), data.begin(), data.begin() + len, actual.begin(),
+                               actual.begin() + len, trash, pred);
+        invoke_on_all_policies(test_one_policy(), data.cbegin(), data.cbegin() + len, actual.begin(),
+                               actual.begin() + len, trash, pred);
+    }
+}
+
+int
+main()
+{
+    test<uint8_t, uint32_t>([](uint32_t a, uint32_t b) { return a - b; });
+    test<int32_t, int64_t>([](int64_t a, int64_t b) { return a / (b + 1); });
+    test<int64_t, float32_t>([](float32_t a, float32_t b) { return (a + b) / 2; });
+    test<wrapper<int32_t>, wrapper<int64_t>>(
+        [](const wrapper<int64_t>& a, const wrapper<int64_t>& b) { return a - b; });
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/numerics/numeric.ops/reduce.pass.cpp b/pstl/test/std/numerics/numeric.ops/reduce.pass.cpp
new file mode 100644
index 0000000..b2144b9
--- /dev/null
+++ b/pstl/test/std/numerics/numeric.ops/reduce.pass.cpp
@@ -0,0 +1,114 @@
+// -*- C++ -*-
+//===-- reduce.pass.cpp ---------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <numeric>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct test_long_forms_for_one_policy
+{
+    template <typename Policy, typename Iterator, typename T, typename BinaryOp>
+    void
+    operator()(Policy&& exec, Iterator first, Iterator last, T init, BinaryOp binary, T expected)
+    {
+        T result_r = std::reduce(exec, first, last, init, binary);
+        EXPECT_EQ(expected, result_r, "bad result from reduce(exec, first, last, init, binary_op)");
+    }
+};
+
+template <typename T, typename BinaryOp, typename F>
+void
+test_long_form(T init, BinaryOp binary_op, F f)
+{
+    // Try sequences of various lengths
+    for (size_t n = 0; n <= 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        T expected(init);
+        Sequence<T> in(n, [n, f](size_t k) { return f((int32_t(k ^ n) % 1000 - 500)); });
+        for (size_t k = 0; k < n; ++k)
+            expected = binary_op(expected, in[k]);
+
+        using namespace std;
+
+        T result = transform_reduce_serial(in.cfbegin(), in.cfend(), init, binary_op, [](const T& t) { return t; });
+        EXPECT_EQ(expected, result, "bad result from reduce(first, last, init, binary_op_op)");
+
+        invoke_on_all_policies(test_long_forms_for_one_policy(), in.begin(), in.end(), init, binary_op, expected);
+        invoke_on_all_policies(test_long_forms_for_one_policy(), in.cbegin(), in.cend(), init, binary_op, expected);
+    }
+}
+
+struct test_two_short_forms
+{
+
+#if defined(_PSTL_ICC_16_VC14_TEST_PAR_TBB_RT_RELEASE_64_BROKEN) //dummy specialization by policy type, in case of broken configuration
+    template <typename Iterator>
+    void
+    operator()(pstl::execution::parallel_policy, Iterator first, Iterator last, Sum init, Sum expected)
+    {
+    }
+    template <typename Iterator>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, Iterator first, Iterator last, Sum init, Sum expected)
+    {
+    }
+#endif
+
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator first, Iterator last, Sum init, Sum expected)
+    {
+        using namespace std;
+
+        Sum r0 = init + reduce(exec, first, last);
+        EXPECT_EQ(expected, r0, "bad result from reduce(exec, first, last)");
+
+        Sum r1 = reduce(exec, first, last, init);
+        EXPECT_EQ(expected, r1, "bad result from reduce(exec, first, last, init)");
+    }
+};
+
+// Test forms of reduce(...) that omit the binary_op or init operands.
+void
+test_short_forms()
+{
+    for (size_t n = 0; n <= 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        Sum init(42, OddTag());
+        Sum expected(init);
+        Sequence<Sum> in(n, [n](size_t k) { return Sum((int32_t(k ^ n) % 1000 - 500), OddTag()); });
+        for (size_t k = 0; k < n; ++k)
+            expected = expected + in[k];
+        invoke_on_all_policies(test_two_short_forms(), in.begin(), in.end(), init, expected);
+        invoke_on_all_policies(test_two_short_forms(), in.cbegin(), in.cend(), init, expected);
+    }
+}
+
+int
+main()
+{
+    // Test for popular types
+    test_long_form(42, std::plus<int32_t>(), [](int32_t x) { return x; });
+    test_long_form(42.0, std::plus<float64_t>(), [](float64_t x) { return x; });
+
+    // Test for strict types
+    test_long_form<Number>(Number(42, OddTag()), Add(OddTag()), [](int32_t x) { return Number(x, OddTag()); });
+
+    // Short forms are just facade for long forms, so just test with a single type.
+    test_short_forms();
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/numerics/numeric.ops/scan.fail.cpp b/pstl/test/std/numerics/numeric.ops/scan.fail.cpp
new file mode 100644
index 0000000..b17944a
--- /dev/null
+++ b/pstl/test/std/numerics/numeric.ops/scan.fail.cpp
@@ -0,0 +1,28 @@
+// -*- C++ -*-
+//===-- scan.fail.cpp -----------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include <execution>
+#include <numeric>
+
+struct CustomPolicy
+{
+} policy;
+
+int32_t
+main()
+{
+    int *first = nullptr, *last = nullptr, *result = nullptr;
+
+    std::exclusive_scan(policy, first, last, result, 0); // expected-error {{no matching function for call to 'exclusive_scan'}}
+    std::exclusive_scan(policy, first, last, result, 0, std::plus<int>()); // expected-error {{no matching function for call to 'exclusive_scan'}}
+
+    return 0;
+}
diff --git a/pstl/test/std/numerics/numeric.ops/scan.pass.cpp b/pstl/test/std/numerics/numeric.ops/scan.pass.cpp
new file mode 100644
index 0000000..e89edc7
--- /dev/null
+++ b/pstl/test/std/numerics/numeric.ops/scan.pass.cpp
@@ -0,0 +1,201 @@
+// -*- C++ -*-
+//===-- scan.pass.cpp -----------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <numeric>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+// We provide the no execution policy versions of the exclusive_scan and inclusive_scan due checking correctness result of the versions with execution policies.
+//TODO: to add a macro for availability of ver implementations
+template <class InputIterator, class OutputIterator, class T>
+OutputIterator
+exclusive_scan_serial(InputIterator first, InputIterator last, OutputIterator result, T init)
+{
+    for (; first != last; ++first, ++result)
+    {
+        *result = init;
+        init = init + *first;
+    }
+    return result;
+}
+
+template <class InputIterator, class OutputIterator, class T, class BinaryOperation>
+OutputIterator
+exclusive_scan_serial(InputIterator first, InputIterator last, OutputIterator result, T init, BinaryOperation binary_op)
+{
+    for (; first != last; ++first, ++result)
+    {
+        *result = init;
+        init = binary_op(init, *first);
+    }
+    return result;
+}
+
+// Note: N4582 is missing the ", class T".  Issue was reported 2016-Apr-11 to cxxeditor@gmail.com
+template <class InputIterator, class OutputIterator, class BinaryOperation, class T>
+OutputIterator
+inclusive_scan_serial(InputIterator first, InputIterator last, OutputIterator result, BinaryOperation binary_op, T init)
+{
+    for (; first != last; ++first, ++result)
+    {
+        init = binary_op(init, *first);
+        *result = init;
+    }
+    return result;
+}
+
+template <class InputIterator, class OutputIterator, class BinaryOperation>
+OutputIterator
+inclusive_scan_serial(InputIterator first, InputIterator last, OutputIterator result, BinaryOperation binary_op)
+{
+    if (first != last)
+    {
+        auto tmp = *first;
+        *result = tmp;
+        return inclusive_scan_serial(++first, last, ++result, binary_op, tmp);
+    }
+    else
+    {
+        return result;
+    }
+}
+
+template <class InputIterator, class OutputIterator>
+OutputIterator
+inclusive_scan_serial(InputIterator first, InputIterator last, OutputIterator result)
+{
+    typedef typename std::iterator_traits<InputIterator>::value_type input_type;
+    return inclusive_scan_serial(first, last, result, std::plus<input_type>());
+}
+
+// Most of the framework required for testing inclusive and exclusive scan is identical,
+// so the tests for both are in this file.  Which is being tested is controlled by the global
+// flag inclusive, which is set to each alternative by main().
+static bool inclusive;
+
+template <typename Iterator, typename Size, typename T>
+void
+check_and_reset(Iterator expected_first, Iterator out_first, Size n, T trash)
+{
+    EXPECT_EQ_N(expected_first, out_first, n,
+                inclusive ? "wrong result from inclusive_scan" : "wrong result from exclusive_scan");
+    std::fill_n(out_first, n, trash);
+}
+
+struct test_scan_with_plus
+{
+    template <typename Policy, typename Iterator1, typename Iterator2, typename Iterator3, typename Size, typename T>
+    void
+    operator()(Policy&& exec, Iterator1 in_first, Iterator1 in_last, Iterator2 out_first, Iterator2 out_last,
+               Iterator3 expected_first, Iterator3, Size n, T init, T trash)
+    {
+        using namespace std;
+
+        auto orr1 = inclusive ? inclusive_scan_serial(in_first, in_last, expected_first)
+                              : exclusive_scan_serial(in_first, in_last, expected_first, init);
+        (void)orr1;
+        auto orr = inclusive ? inclusive_scan(exec, in_first, in_last, out_first)
+                             : exclusive_scan(exec, in_first, in_last, out_first, init);
+        EXPECT_TRUE(out_last == orr,
+                    inclusive ? "inclusive_scan returned wrong iterator" : "exclusive_scan returned wrong iterator");
+
+        check_and_reset(expected_first, out_first, n, trash);
+        fill(out_first, out_last, trash);
+    }
+};
+
+template <typename T, typename Convert>
+void
+test_with_plus(T init, T trash, Convert convert)
+{
+    for (size_t n = 0; n <= 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        Sequence<T> in(n, convert);
+        Sequence<T> expected(in);
+        Sequence<T> out(n, [&](int32_t) { return trash; });
+
+        invoke_on_all_policies(test_scan_with_plus(), in.begin(), in.end(), out.begin(), out.end(), expected.begin(),
+                               expected.end(), in.size(), init, trash);
+        invoke_on_all_policies(test_scan_with_plus(), in.cbegin(), in.cend(), out.begin(), out.end(), expected.begin(),
+                               expected.end(), in.size(), init, trash);
+    }
+}
+struct test_scan_with_binary_op
+{
+    template <typename Policy, typename Iterator1, typename Iterator2, typename Iterator3, typename Size, typename T,
+              typename BinaryOp>
+    typename std::enable_if<!TestUtils::isReverse<Iterator1>::value, void>::type
+    operator()(Policy&& exec, Iterator1 in_first, Iterator1 in_last, Iterator2 out_first, Iterator2 out_last,
+               Iterator3 expected_first, Iterator3, Size n, T init, BinaryOp binary_op, T trash)
+    {
+        using namespace std;
+
+        auto orr1 = inclusive ? inclusive_scan_serial(in_first, in_last, expected_first, binary_op, init)
+                              : exclusive_scan_serial(in_first, in_last, expected_first, init, binary_op);
+        (void)orr1;
+        auto orr = inclusive ? inclusive_scan(exec, in_first, in_last, out_first, binary_op, init)
+                             : exclusive_scan(exec, in_first, in_last, out_first, init, binary_op);
+
+        EXPECT_TRUE(out_last == orr, "scan returned wrong iterator");
+        check_and_reset(expected_first, out_first, n, trash);
+    }
+
+    template <typename Policy, typename Iterator1, typename Iterator2, typename Iterator3, typename Size, typename T,
+              typename BinaryOp>
+    typename std::enable_if<TestUtils::isReverse<Iterator1>::value, void>::type
+    operator()(Policy&&, Iterator1, Iterator1, Iterator2, Iterator2, Iterator3, Iterator3, Size, T, BinaryOp, T)
+    {
+    }
+};
+
+template <typename In, typename Out, typename BinaryOp>
+void
+test_matrix(Out init, BinaryOp binary_op, Out trash)
+{
+    for (size_t n = 0; n <= 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        Sequence<In> in(n, [](size_t k) { return In(k, k + 1); });
+
+        Sequence<Out> out(n, [&](size_t) { return trash; });
+        Sequence<Out> expected(n, [&](size_t) { return trash; });
+
+        invoke_on_all_policies(test_scan_with_binary_op(), in.begin(), in.end(), out.begin(), out.end(),
+                               expected.begin(), expected.end(), in.size(), init, binary_op, trash);
+        invoke_on_all_policies(test_scan_with_binary_op(), in.cbegin(), in.cend(), out.begin(), out.end(),
+                               expected.begin(), expected.end(), in.size(), init, binary_op, trash);
+    }
+}
+
+int
+main()
+{
+    for (int32_t mode = 0; mode < 2; ++mode)
+    {
+        inclusive = mode != 0;
+#if !defined(_PSTL_ICC_19_TEST_SIMD_UDS_WINDOWS_RELEASE_BROKEN)
+        // Test with highly restricted type and associative but not commutative operation
+        test_matrix<Matrix2x2<int32_t>, Matrix2x2<int32_t>>(Matrix2x2<int32_t>(), multiply_matrix<int32_t>,
+                                                            Matrix2x2<int32_t>(-666, 666));
+#endif
+
+        // Since the implict "+" forms of the scan delegate to the generic forms,
+        // there's little point in using a highly restricted type, so just use double.
+        test_with_plus<float64_t>(inclusive ? 0.0 : -1.0, -666.0,
+                                  [](uint32_t k) { return float64_t((k % 991 + 1) ^ (k % 997 + 2)); });
+    }
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/numerics/numeric.ops/transform_reduce.pass.cpp b/pstl/test/std/numerics/numeric.ops/transform_reduce.pass.cpp
new file mode 100644
index 0000000..f9c4538
--- /dev/null
+++ b/pstl/test/std/numerics/numeric.ops/transform_reduce.pass.cpp
@@ -0,0 +1,129 @@
+// -*- C++ -*-
+//===-- transform_reduce.pass.cpp -----------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <numeric>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+// Functor for xor-operation for modeling binary operations in inner_product
+class XOR
+{
+  public:
+    template <typename T>
+    T
+    operator()(const T& left, const T& right) const
+    {
+        return left ^ right;
+    }
+};
+
+// Model of User-defined class
+class MyClass
+{
+  public:
+    int32_t my_field;
+    MyClass() { my_field = 0; }
+    MyClass(int32_t in) { my_field = in; }
+    MyClass(const MyClass& in) = default;
+
+    friend MyClass
+    operator+(const MyClass& x, const MyClass& y)
+    {
+        return MyClass(x.my_field + y.my_field);
+    }
+    friend MyClass
+    operator-(const MyClass& x)
+    {
+        return MyClass(-x.my_field);
+    }
+    friend MyClass operator*(const MyClass& x, const MyClass& y)
+    {
+        return MyClass(x.my_field * y.my_field);
+    }
+    friend bool operator==(const MyClass& x, const MyClass& y)
+    {
+        return x.my_field == y.my_field;
+    }
+};
+
+template <typename T>
+void
+CheckResults(const T& expected, const T& in)
+{
+    EXPECT_TRUE(expected == in, "wrong result of transform_reduce");
+}
+
+// We need to check correctness only for "int" (for example) except cases
+// if we have "floating-point type"-specialization
+void
+CheckResults(const float32_t&, const float32_t&)
+{
+}
+
+// Test for different types and operations with different iterators
+struct test_transform_reduce
+{
+    template <typename Policy, typename InputIterator1, typename InputIterator2, typename T, typename BinaryOperation1,
+              typename BinaryOperation2, typename UnaryOp>
+    void
+    operator()(Policy&& exec, InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2,
+               T init, BinaryOperation1 opB1, BinaryOperation2 opB2, UnaryOp opU)
+    {
+
+        auto expectedB = std::inner_product(first1, last1, first2, init, opB1, opB2);
+        auto expectedU = transform_reduce_serial(first1, last1, init, opB1, opU);
+        T resRA = std::transform_reduce(exec, first1, last1, first2, init, opB1, opB2);
+        CheckResults(expectedB, resRA);
+        resRA = std::transform_reduce(exec, first1, last1, init, opB1, opU);
+        CheckResults(expectedU, resRA);
+    }
+};
+
+template <typename T, typename BinaryOperation1, typename BinaryOperation2, typename UnaryOp, typename Initializer>
+void
+test_by_type(T init, BinaryOperation1 opB1, BinaryOperation2 opB2, UnaryOp opU, Initializer initObj)
+{
+
+    std::size_t maxSize = 100000;
+    Sequence<T> in1(maxSize, initObj);
+    Sequence<T> in2(maxSize, initObj);
+
+    for (std::size_t n = 0; n < maxSize; n = n < 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        invoke_on_all_policies(test_transform_reduce(), in1.begin(), in1.begin() + n, in2.begin(), in2.begin() + n,
+                               init, opB1, opB2, opU);
+        invoke_on_all_policies(test_transform_reduce(), in1.cbegin(), in1.cbegin() + n, in2.cbegin(), in2.cbegin() + n,
+                               init, opB1, opB2, opU);
+    }
+}
+
+int
+main()
+{
+    test_by_type<int32_t>(42, std::plus<int32_t>(), std::multiplies<int32_t>(), std::negate<int32_t>(),
+                          [](std::size_t) -> int32_t { return int32_t(rand() % 1000); });
+    test_by_type<int64_t>(0, [](const int64_t& a, const int64_t& b) -> int64_t { return a | b; }, XOR(),
+                          [](const int64_t& x) -> int64_t { return x * 2; },
+                          [](std::size_t) -> int64_t { return int64_t(rand() % 1000); });
+    test_by_type<float32_t>(
+        1.0f, std::multiplies<float32_t>(), [](const float32_t& a, const float32_t& b) -> float32_t { return a + b; },
+        [](const float32_t& x) -> float32_t { return x + 2; }, [](std::size_t) -> float32_t { return rand() % 1000; });
+    test_by_type<MyClass>(MyClass(), std::plus<MyClass>(), std::multiplies<MyClass>(), std::negate<MyClass>(),
+                          [](std::size_t) -> MyClass { return MyClass(rand() % 1000); });
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/numerics/numeric.ops/transform_scan.pass.cpp b/pstl/test/std/numerics/numeric.ops/transform_scan.pass.cpp
new file mode 100644
index 0000000..95294e4
--- /dev/null
+++ b/pstl/test/std/numerics/numeric.ops/transform_scan.pass.cpp
@@ -0,0 +1,177 @@
+// -*- C++ -*-
+//===-- transform_scan.pass.cpp -------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <numeric>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+// Most of the framework required for testing inclusive and exclusive transform-scans is identical,
+// so the tests for both are in this file.  Which is being tested is controlled by the global
+// flag inclusive, which is set to each alternative by main().
+static bool inclusive;
+
+template <typename Iterator, typename Size, typename T>
+void
+check_and_reset(Iterator expected_first, Iterator out_first, Size n, T trash)
+{
+    EXPECT_EQ_N(expected_first, out_first, n,
+                inclusive ? "wrong result from transform_inclusive_scan"
+                          : "wrong result from transform_exclusive_scan");
+    std::fill_n(out_first, n, trash);
+}
+
+struct test_transform_scan
+{
+    template <typename Policy, typename InputIterator, typename OutputIterator, typename Size, typename UnaryOp,
+              typename T, typename BinaryOp>
+    typename std::enable_if<!TestUtils::isReverse<InputIterator>::value, void>::type
+    operator()(Policy&& exec, InputIterator first, InputIterator last, OutputIterator out_first,
+               OutputIterator out_last, OutputIterator expected_first, OutputIterator, Size n, UnaryOp unary_op, T init,
+               BinaryOp binary_op, T trash)
+    {
+        using namespace std;
+
+        auto orr1 =
+            inclusive
+                ? transform_inclusive_scan(std::execution::seq, first, last, expected_first, binary_op, unary_op, init)
+                : transform_exclusive_scan(std::execution::seq, first, last, expected_first, init, binary_op, unary_op);
+        auto orr2 = inclusive ? transform_inclusive_scan(exec, first, last, out_first, binary_op, unary_op, init)
+                              : transform_exclusive_scan(exec, first, last, out_first, init, binary_op, unary_op);
+        EXPECT_TRUE(out_last == orr2, "transform...scan returned wrong iterator");
+        check_and_reset(expected_first, out_first, n, trash);
+
+        // Checks inclusive scan if init is not provided
+        if (inclusive && n > 0)
+        {
+            orr1 = transform_inclusive_scan(std::execution::seq, first, last, expected_first, binary_op, unary_op);
+            orr2 = transform_inclusive_scan(exec, first, last, out_first, binary_op, unary_op);
+            EXPECT_TRUE(out_last == orr2, "transform...scan returned wrong iterator");
+            check_and_reset(expected_first, out_first, n, trash);
+        }
+    }
+
+    template <typename Policy, typename InputIterator, typename OutputIterator, typename Size, typename UnaryOp,
+              typename T, typename BinaryOp>
+    typename std::enable_if<TestUtils::isReverse<InputIterator>::value, void>::type
+    operator()(Policy&&, InputIterator, InputIterator, OutputIterator, OutputIterator, OutputIterator, OutputIterator,
+               Size, UnaryOp, T, BinaryOp, T)
+    {
+    }
+};
+
+const uint32_t encryption_mask = 0x314;
+
+template <typename InputIterator, typename OutputIterator, typename UnaryOperation, typename T,
+          typename BinaryOperation>
+std::pair<OutputIterator, T>
+transform_inclusive_scan_serial(InputIterator first, InputIterator last, OutputIterator result, UnaryOperation unary_op,
+                                T init, BinaryOperation binary_op) noexcept
+{
+    for (; first != last; ++first, ++result)
+    {
+        init = binary_op(init, unary_op(*first));
+        *result = init;
+    }
+    return std::make_pair(result, init);
+}
+
+template <typename InputIterator, typename OutputIterator, typename UnaryOperation, typename T,
+          typename BinaryOperation>
+std::pair<OutputIterator, T>
+transform_exclusive_scan_serial(InputIterator first, InputIterator last, OutputIterator result, UnaryOperation unary_op,
+                                T init, BinaryOperation binary_op) noexcept
+{
+    for (; first != last; ++first, ++result)
+    {
+        *result = init;
+        init = binary_op(init, unary_op(*first));
+    }
+    return std::make_pair(result, init);
+}
+
+template <typename In, typename Out, typename UnaryOp, typename BinaryOp>
+void
+test(UnaryOp unary_op, Out init, BinaryOp binary_op, Out trash)
+{
+    for (size_t n = 0; n <= 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        Sequence<In> in(n, [](size_t k) { return In(k ^ encryption_mask); });
+
+        Out tmp = init;
+        Sequence<Out> expected(n, [&](size_t k) -> Out {
+            if (inclusive)
+            {
+                tmp = binary_op(tmp, unary_op(in[k]));
+                return tmp;
+            }
+            else
+            {
+                Out val = tmp;
+                tmp = binary_op(tmp, unary_op(in[k]));
+                return val;
+            }
+        });
+
+        Sequence<Out> out(n, [&](size_t) { return trash; });
+
+        auto result =
+            inclusive
+                ? transform_inclusive_scan_serial(in.cbegin(), in.cend(), out.fbegin(), unary_op, init, binary_op)
+                : transform_exclusive_scan_serial(in.cbegin(), in.cend(), out.fbegin(), unary_op, init, binary_op);
+        (void)result;
+        check_and_reset(expected.begin(), out.begin(), out.size(), trash);
+
+        invoke_on_all_policies(test_transform_scan(), in.begin(), in.end(), out.begin(), out.end(), expected.begin(),
+                               expected.end(), in.size(), unary_op, init, binary_op, trash);
+        invoke_on_all_policies(test_transform_scan(), in.cbegin(), in.cend(), out.begin(), out.end(), expected.begin(),
+                               expected.end(), in.size(), unary_op, init, binary_op, trash);
+    }
+}
+
+template <typename In, typename Out, typename UnaryOp, typename BinaryOp>
+void
+test_matrix(UnaryOp unary_op, Out init, BinaryOp binary_op, Out trash)
+{
+    for (size_t n = 0; n <= 100000; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        Sequence<In> in(n, [](size_t k) { return In(k, k + 1); });
+
+        Sequence<Out> out(n, [&](size_t) { return trash; });
+        Sequence<Out> expected(n, [&](size_t) { return trash; });
+
+        invoke_on_all_policies(test_transform_scan(), in.begin(), in.end(), out.begin(), out.end(), expected.begin(),
+                               expected.end(), in.size(), unary_op, init, binary_op, trash);
+        invoke_on_all_policies(test_transform_scan(), in.cbegin(), in.cend(), out.begin(), out.end(), expected.begin(),
+                               expected.end(), in.size(), unary_op, init, binary_op, trash);
+    }
+}
+
+int
+main()
+{
+    for (int32_t mode = 0; mode < 2; ++mode)
+    {
+        inclusive = mode != 0;
+#if !defined(_PSTL_ICC_19_TEST_SIMD_UDS_WINDOWS_RELEASE_BROKEN)
+        test_matrix<Matrix2x2<int32_t>, Matrix2x2<int32_t>>([](const Matrix2x2<int32_t> x) { return x; },
+                                                            Matrix2x2<int32_t>(), multiply_matrix<int32_t>,
+                                                            Matrix2x2<int32_t>(-666, 666));
+#endif
+        test<int32_t, uint32_t>([](int32_t x) { return x++; }, -123, [](int32_t x, int32_t y) { return x + y; }, 666);
+    }
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/utilities/memory/specialized.algorithms/uninitialized_construct.pass.cpp b/pstl/test/std/utilities/memory/specialized.algorithms/uninitialized_construct.pass.cpp
new file mode 100644
index 0000000..a5bdbb3
--- /dev/null
+++ b/pstl/test/std/utilities/memory/specialized.algorithms/uninitialized_construct.pass.cpp
@@ -0,0 +1,123 @@
+// -*- C++ -*-
+//===-- uninitialized_construct.pass.cpp ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+// Tests for uninitialized_default_construct, uninitialized_default_construct_n,
+//           uninitialized_value_construct,   uninitialized_value_construct_n
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <memory>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+// function of checking correctness for uninitialized.construct.value
+template <typename T, typename Iterator>
+bool
+IsCheckValueCorrectness(Iterator begin, Iterator end)
+{
+    for (; begin != end; ++begin)
+    {
+        if (*begin != T())
+        {
+            return false;
+        }
+    }
+    return true;
+}
+
+struct test_uninit_construct
+{
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator begin, Iterator end, size_t n, /*is_trivial<T>=*/std::false_type)
+    {
+        typedef typename std::iterator_traits<Iterator>::value_type T;
+        // it needs for cleaning memory that was filled by default constructors in unique_ptr<T[]> p(new T[n])
+        // and for cleaning memory after last calling of uninitialized_value_construct_n.
+        // It is important for non-trivial types
+        std::destroy_n(exec, begin, n);
+
+        // reset counter of constructors
+        T::SetCount(0);
+        // run algorithm
+        std::uninitialized_default_construct(exec, begin, end);
+        // compare counter of constructors to length of container
+        EXPECT_TRUE(T::Count() == n, "wrong uninitialized_default_construct");
+        // destroy objects for testing new algorithms on same memory
+        std::destroy(exec, begin, end);
+
+        std::uninitialized_default_construct_n(exec, begin, n);
+        EXPECT_TRUE(T::Count() == n, "wrong uninitialized_default_construct_n");
+        std::destroy_n(exec, begin, n);
+
+        std::uninitialized_value_construct(exec, begin, end);
+        EXPECT_TRUE(T::Count() == n, "wrong uninitialized_value_construct");
+        std::destroy(exec, begin, end);
+
+        std::uninitialized_value_construct_n(exec, begin, n);
+        EXPECT_TRUE(T::Count() == n, "wrong uninitialized_value_construct_n");
+    }
+
+    template <typename Policy, typename Iterator>
+    void
+    operator()(Policy&& exec, Iterator begin, Iterator end, size_t n, /*is_trivial<T>=*/std::true_type)
+    {
+        typedef typename std::iterator_traits<Iterator>::value_type T;
+
+        std::uninitialized_default_construct(exec, begin, end);
+        std::destroy(exec, begin, end);
+
+        std::uninitialized_default_construct_n(exec, begin, n);
+        std::destroy_n(exec, begin, n);
+
+        std::uninitialized_value_construct(exec, begin, end);
+        // check correctness for uninitialized.construct.value
+        EXPECT_TRUE(IsCheckValueCorrectness<T>(begin, end), "wrong uninitialized_value_construct");
+        std::destroy(exec, begin, end);
+
+        std::uninitialized_value_construct_n(exec, begin, n);
+        EXPECT_TRUE(IsCheckValueCorrectness<T>(begin, end), "wrong uninitialized_value_construct_n");
+        std::destroy_n(exec, begin, n);
+    }
+};
+
+template <typename T>
+void
+test_uninit_construct_by_type()
+{
+    std::size_t N = 100000;
+    for (size_t n = 0; n <= N; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        std::unique_ptr<T[]> p(new T[n]);
+        invoke_on_all_policies(test_uninit_construct(), p.get(), std::next(p.get(), n), n, std::is_trivial<T>());
+    }
+}
+
+int
+main()
+{
+
+    // for user-defined types
+#if !defined(_PSTL_ICC_16_VC14_TEST_PAR_TBB_RT_RELEASE_64_BROKEN)
+    test_uninit_construct_by_type<Wrapper<int32_t>>();
+    test_uninit_construct_by_type<Wrapper<std::vector<std::string>>>();
+#endif
+
+    // for trivial types
+    test_uninit_construct_by_type<int8_t>();
+    test_uninit_construct_by_type<float64_t>();
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/utilities/memory/specialized.algorithms/uninitialized_copy_move.pass.cpp b/pstl/test/std/utilities/memory/specialized.algorithms/uninitialized_copy_move.pass.cpp
new file mode 100644
index 0000000..21186b4
--- /dev/null
+++ b/pstl/test/std/utilities/memory/specialized.algorithms/uninitialized_copy_move.pass.cpp
@@ -0,0 +1,143 @@
+// -*- C++ -*-
+//===-- uninitialized_copy_move.pass.cpp ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+// Tests for uninitialized_copy, uninitialized_copy_n, uninitialized_move, uninitialized_move_n
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <memory>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+// function of checking correctness for uninitialized.construct.value
+template <typename InputIterator, typename OutputIterator, typename Size>
+bool
+IsCheckValueCorrectness(InputIterator first1, OutputIterator first2, Size n)
+{
+    for (Size i = 0; i < n; ++i, ++first1, ++first2)
+    {
+        if (*first1 != *first2)
+        {
+            return false;
+        }
+    }
+    return true;
+}
+
+struct test_uninitialized_copy_move
+{
+    template <typename Policy, typename InputIterator, typename OutputIterator>
+    void
+    operator()(Policy&& exec, InputIterator first, InputIterator last, OutputIterator out_first, size_t n,
+               /*is_trivial<T>=*/std::false_type)
+    {
+        typedef typename std::iterator_traits<InputIterator>::value_type T;
+        // it needs for cleaning memory that was filled by default constructors in unique_ptr<T[]> p(new T[n])
+        // and for cleaning memory after last calling of uninitialized_value_construct_n.
+        // It is important for non-trivial types
+        std::destroy_n(exec, out_first, n);
+
+        // reset counter of constructors
+        T::SetCount(0);
+        // run algorithm
+        std::uninitialized_copy(exec, first, last, out_first);
+        // compare counter of constructors to length of container
+        EXPECT_TRUE(T::Count() == n, "wrong uninitialized_copy");
+        // destroy objects for testing new algorithms on same memory
+        std::destroy_n(exec, out_first, n);
+
+        std::uninitialized_copy_n(exec, first, n, out_first);
+        EXPECT_TRUE(T::Count() == n, "wrong uninitialized_copy_n");
+        std::destroy_n(exec, out_first, n);
+
+        // For move
+        std::uninitialized_move(exec, first, last, out_first);
+        // compare counter of constructors to length of container
+        EXPECT_TRUE(T::MoveCount() == n, "wrong uninitialized_move");
+        // destroy objects for testing new algorithms on same memory
+        std::destroy_n(exec, out_first, n);
+
+        std::uninitialized_move_n(exec, first, n, out_first);
+        EXPECT_TRUE(T::MoveCount() == n, "wrong uninitialized_move_n");
+        std::destroy_n(exec, out_first, n);
+    }
+
+#if defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) || defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN)
+    template <typename InputIterator, typename OutputIterator>
+    void
+    operator()(pstl::execution::unsequenced_policy, InputIterator first, InputIterator last, OutputIterator out_first,
+               size_t n, /*is_trivial<T>=*/std::true_type)
+    {
+    }
+    template <typename InputIterator, typename OutputIterator>
+    void
+    operator()(pstl::execution::parallel_unsequenced_policy, InputIterator first, InputIterator last,
+               OutputIterator out_first, size_t n, /*is_trivial<T>=*/std::true_type)
+    {
+    }
+#endif
+
+    template <typename Policy, typename InputIterator, typename OutputIterator>
+    void
+    operator()(Policy&& exec, InputIterator first, InputIterator last, OutputIterator out_first, size_t n,
+               /*is_trivial<T>=*/std::true_type)
+    {
+        std::uninitialized_copy(exec, first, last, out_first);
+        EXPECT_TRUE(IsCheckValueCorrectness(first, out_first, n), "wrong uninitialized_copy");
+        std::destroy_n(exec, out_first, n);
+
+        std::uninitialized_copy_n(exec, first, n, out_first);
+        EXPECT_TRUE(IsCheckValueCorrectness(first, out_first, n), "wrong uninitialized_copy_n");
+        std::destroy_n(exec, out_first, n);
+
+        std::uninitialized_move(exec, first, last, out_first);
+        EXPECT_TRUE(IsCheckValueCorrectness(first, out_first, n), "wrong uninitialized_move");
+        std::destroy_n(exec, out_first, n);
+
+        std::uninitialized_move_n(exec, first, n, out_first);
+        EXPECT_TRUE(IsCheckValueCorrectness(first, out_first, n), "wrong uninitialized_move_n");
+        std::destroy_n(exec, out_first, n);
+    }
+};
+
+template <typename T>
+void
+test_uninitialized_copy_move_by_type()
+{
+    std::size_t N = 100000;
+    for (size_t n = 0; n <= N; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        Sequence<T> in(n, [=](size_t k) -> T { return T(k); });
+        std::unique_ptr<T[]> p(new T[n]);
+        invoke_on_all_policies(test_uninitialized_copy_move(), in.begin(), in.end(), p.get(), n, std::is_trivial<T>());
+    }
+}
+
+int
+main()
+{
+
+    // for trivial types
+    test_uninitialized_copy_move_by_type<int16_t>();
+    test_uninitialized_copy_move_by_type<float64_t>();
+
+    // for user-defined types
+#if !defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) && !defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) &&     \
+    !defined(_PSTL_ICC_16_VC14_TEST_PAR_TBB_RT_RELEASE_64_BROKEN)
+    test_uninitialized_copy_move_by_type<Wrapper<int8_t>>();
+#endif
+
+    std::cout << done() << std::endl;
+    return 0;
+}
diff --git a/pstl/test/std/utilities/memory/specialized.algorithms/uninitialized_fill_destroy.pass.cpp b/pstl/test/std/utilities/memory/specialized.algorithms/uninitialized_fill_destroy.pass.cpp
new file mode 100644
index 0000000..d579ea5
--- /dev/null
+++ b/pstl/test/std/utilities/memory/specialized.algorithms/uninitialized_fill_destroy.pass.cpp
@@ -0,0 +1,93 @@
+// -*- C++ -*-
+//===-- uninitialized_fill_destroy.pass.cpp -------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+
+#include "support/pstl_test_config.h"
+
+#include <execution>
+#include <memory>
+
+#include "support/utils.h"
+
+using namespace TestUtils;
+
+struct test_uninitialized_fill_destroy
+{
+    template <typename Policy, typename Iterator, typename T>
+    void
+    operator()(Policy&& exec, Iterator first, Iterator last, const T& in, std::size_t n, std::false_type)
+    {
+        using namespace std;
+        {
+            T::SetCount(0);
+            uninitialized_fill(exec, first, last, in);
+            size_t count = count_if(first, last, [&in](T& x) -> bool { return x == in; });
+            EXPECT_TRUE(n == count, "wrong work of uninitialized_fill");
+            destroy(exec, first, last);
+            EXPECT_TRUE(T::Count() == 0, "wrong work of destroy");
+        }
+
+        {
+            auto res = uninitialized_fill_n(exec, first, n, in);
+            EXPECT_TRUE(res == last, "wrong result of uninitialized_fill_n");
+            size_t count = count_if(first, last, [&in](T& x) -> bool { return x == in; });
+            EXPECT_TRUE(n == count, "wrong work of uninitialized_fill_n");
+            destroy_n(exec, first, n);
+            EXPECT_TRUE(T::Count() == 0, "wrong work of destroy_n");
+        }
+    }
+    template <typename Policy, typename Iterator, typename T>
+    void
+    operator()(Policy&& exec, Iterator first, Iterator last, const T& in, std::size_t n, std::true_type)
+    {
+        using namespace std;
+        {
+            destroy(exec, first, last);
+            uninitialized_fill(exec, first, last, in);
+            size_t count = count_if(first, last, [&in](T& x) -> bool { return x == in; });
+            EXPECT_EQ(n, count, "wrong work of uninitialized:_fill");
+        }
+        {
+            destroy_n(exec, first, n);
+            auto res = uninitialized_fill_n(exec, first, n, in);
+            size_t count = count_if(first, last, [&in](T& x) -> bool { return x == in; });
+            EXPECT_EQ(n, count, "wrong work of uninitialized_fill_n");
+            EXPECT_TRUE(res == last, "wrong result of uninitialized_fill_n");
+        }
+    }
+};
+
+template <typename T>
+void
+test_uninitialized_fill_destroy_by_type()
+{
+    std::size_t N = 100000;
+    for (size_t n = 0; n <= N; n = n <= 16 ? n + 1 : size_t(3.1415 * n))
+    {
+        std::unique_ptr<T[]> p(new T[n]);
+        invoke_on_all_policies(test_uninitialized_fill_destroy(), p.get(), std::next(p.get(), n), T(), n,
+                               std::is_trivial<T>());
+    }
+}
+
+int
+main()
+{
+    // for trivial types
+    test_uninitialized_fill_destroy_by_type<int32_t>();
+    test_uninitialized_fill_destroy_by_type<float64_t>();
+
+    // for user-defined types
+    test_uninitialized_fill_destroy_by_type<Wrapper<std::string>>();
+    test_uninitialized_fill_destroy_by_type<Wrapper<int8_t*>>();
+    std::cout << done() << std::endl;
+
+    return 0;
+}
diff --git a/pstl/test/support/pstl_test_config.h b/pstl/test/support/pstl_test_config.h
new file mode 100644
index 0000000..daf5625
--- /dev/null
+++ b/pstl/test/support/pstl_test_config.h
@@ -0,0 +1,52 @@
+// -*- C++ -*-
+//===-- pstl_test_config.h ------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _PSTL_TEST_config_H
+#define _PSTL_TEST_config_H
+
+#if defined(_MSC_VER) && defined(_DEBUG)
+#    define _SCL_SECURE_NO_WARNINGS //to prevent the compilation warning. Microsoft STL implementation has specific checking of an iterator range in DEBUG mode for the containers from the standard library.
+#endif
+
+#ifndef __clang__
+#    define _PSTL_ICC_16_17_TEST_REDUCTION_BOOL_TYPE_RELEASE_64_BROKEN                                                 \
+        (__x86_64 && !_DEBUG && __INTEL_COMPILER && __INTEL_COMPILER <= 1700 && !__APPLE__)
+#    define _PSTL_ICC_16_17_TEST_REDUCTION_RELEASE_BROKEN                                                              \
+        (!_DEBUG && __INTEL_COMPILER &&                                                                                \
+         (__INTEL_COMPILER < 1800 || (__INTEL_COMPILER == 1800 && __INTEL_COMPILER_UPDATE < 1)))
+#    define _PSTL_ICC_1800_TEST_MONOTONIC_RELEASE_64_BROKEN                                                            \
+        (__x86_64 && !_DEBUG && __INTEL_COMPILER && __INTEL_COMPILER == 1800 && __INTEL_COMPILER_UPDATE < 1)
+#    define _PSTL_ICC_17_TEST_MAC_RELEASE_32_BROKEN                                                                    \
+        (__i386__ && !_DEBUG && __INTEL_COMPILER >= 1700 && __INTEL_COMPILER < 1800 && __APPLE__)
+#    define _PSTL_ICC_18_VC141_TEST_SIMD_LAMBDA_RELEASE_BROKEN                                                         \
+        (!_DEBUG && __INTEL_COMPILER >= 1800 && __INTEL_COMPILER < 1900 && _MSC_VER == 1910)
+#    define _PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN                                                        \
+        (_M_IX86 && _DEBUG && __INTEL_COMPILER >= 1700 && __INTEL_COMPILER < 1800 && _MSC_VER >= 1900)
+#    define _PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN                                                         \
+        (_M_IX86 && _DEBUG && __INTEL_COMPILER >= 1600 && __INTEL_COMPILER < 1700 && _MSC_VER == 1900)
+#    define _PSTL_ICC_16_VC14_TEST_PAR_TBB_RT_RELEASE_64_BROKEN                                                        \
+        (((_M_X64 && _MSC_VER == 1900) || __x86_64) && !_DEBUG && __INTEL_COMPILER < 1700)
+#    define _PSTL_ICC_16_17_TEST_64_TIMEOUT (__x86_64 && __INTEL_COMPILER && __INTEL_COMPILER < 1800 && !__APPLE__)
+#    define _PSTL_ICC_18_TEST_EARLY_EXIT_MONOTONIC_RELEASE_BROKEN                                                      \
+        (!_DEBUG && __INTEL_COMPILER && __INTEL_COMPILER == 1800)
+#    define _PSTL_CLANG_TEST_BIG_OBJ_DEBUG_32_BROKEN                                                                   \
+        (__i386__ && PSTL_USE_DEBUG && __clang__ && _PSTL_CLANG_VERSION <= 90000)
+#    define _PSTL_ICC_16_17_18_TEST_UNIQUE_MASK_RELEASE_BROKEN                                                         \
+        (!_DEBUG && __INTEL_COMPILER &&                                                                                \
+         (__INTEL_COMPILER < 1800 || (__INTEL_COMPILER == 1800 && __INTEL_COMPILER_UPDATE < 3)))
+#    define _PSTL_ICC_18_TEST_EARLY_EXIT_AVX_RELEASE_BROKEN                                                            \
+        (!_DEBUG && __INTEL_COMPILER == 1800 && __AVX__ && !__AVX2__ && !__AVX512__)
+#    define _PSTL_ICC_19_TEST_IS_PARTITIONED_RELEASE_BROKEN                                                            \
+        (!PSTL_USE_DEBUG && (__linux__ || __APPLE__) && __INTEL_COMPILER == 1900)
+#    define _PSTL_ICL_19_VC14_VC141_TEST_SCAN_RELEASE_BROKEN                                                           \
+        (__INTEL_COMPILER == 1900 && _MSC_VER >= 1900 && _MSC_VER <= 1910)
+#    define _PSTL_ICC_19_TEST_SIMD_UDS_WINDOWS_RELEASE_BROKEN (__INTEL_COMPILER == 1900 && _MSC_VER && !_DEBUG)
+#endif // !__clang__
+
+#endif /* _PSTL_TEST_config_H */
diff --git a/pstl/test/support/stdlib/algorithm b/pstl/test/support/stdlib/algorithm
new file mode 100644
index 0000000..39e6f74
--- /dev/null
+++ b/pstl/test/support/stdlib/algorithm
@@ -0,0 +1,26 @@
+// -*- C++ -*-
+//===-- algorithm ---------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _TEST_SUPPORT_STDLIB_ALGORITHM
+#define _TEST_SUPPORT_STDLIB_ALGORITHM
+
+#include_next <algorithm>
+
+#include <pstl/internal/pstl_config.h>
+
+#if _PSTL_EXECUTION_POLICIES_DEFINED
+// If <execution> has already been included, pull in implementations
+#    include <pstl/internal/glue_algorithm_impl.h>
+#else
+// Otherwise just pull in forward declarations
+#    include <pstl/internal/glue_algorithm_defs.h>
+#    define _PSTL_ALGORITHM_FORWARD_DECLARED 1
+#endif
+
+#endif /* _TEST_SUPPORT_STDLIB_ALGORITHM */
diff --git a/pstl/test/support/stdlib/execution b/pstl/test/support/stdlib/execution
new file mode 100644
index 0000000..ad18c45
--- /dev/null
+++ b/pstl/test/support/stdlib/execution
@@ -0,0 +1,50 @@
+// -*- C++ -*-
+//===-- execution ---------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _TEST_SUPPORT_STDLIB_EXECUTION
+#define _TEST_SUPPORT_STDLIB_EXECUTION
+
+// #include_next <execution> // None of the standard libraries PSTL is built on top have the <execution> header yet.
+
+#include <pstl/internal/pstl_config.h>
+#include <pstl/internal/execution_defs.h>
+
+#define _PSTL_EXECUTION_POLICIES_DEFINED 1
+
+#if _PSTL_ALGORITHM_FORWARD_DECLARED
+#    include <pstl/internal/glue_algorithm_impl.h>
+#endif
+
+#if _PSTL_MEMORY_FORWARD_DECLARED
+#    include <pstl/internal/glue_memory_impl.h>
+#endif
+
+#if _PSTL_NUMERIC_FORWARD_DECLARED
+#    include <pstl/internal/glue_numeric_impl.h>
+#endif
+
+#if _PSTL_CPP17_EXECUTION_POLICIES_PRESENT
+_PSTL_PRAGMA_MESSAGE_POLICIES("The <Parallel STL> execution policies are defined in the namespace __pstl::execution")
+#else
+#    include <pstl/internal/glue_execution_defs.h>
+_PSTL_PRAGMA_MESSAGE_POLICIES(
+    "The <Parallel STL> execution policies are injected into the standard namespace std::execution")
+#endif
+
+//TODO: __pstl::execution namespace is injected into the pstl::execution namespace when the implementation is not a part of
+// standard C++ library
+namespace pstl
+{
+namespace execution
+{
+using namespace __pstl::execution;
+}
+} // namespace pstl
+
+#endif /* _TEST_SUPPORT_STDLIB_EXECUTION */
diff --git a/pstl/test/support/stdlib/memory b/pstl/test/support/stdlib/memory
new file mode 100644
index 0000000..7d110912
--- /dev/null
+++ b/pstl/test/support/stdlib/memory
@@ -0,0 +1,26 @@
+// -*- C++ -*-
+//===-- memory ------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _TEST_SUPPORT_STDLIB_MEMORY
+#define _TEST_SUPPORT_STDLIB_MEMORY
+
+#include_next <memory>
+
+#include <pstl/internal/pstl_config.h>
+
+#if _PSTL_EXECUTION_POLICIES_DEFINED
+// If <execution> has already been included, pull in implementations
+#    include <pstl/internal/glue_memory_impl.h>
+#else
+// Otherwise just pull in forward declarations
+#    include <pstl/internal/glue_memory_defs.h>
+#    define _PSTL_MEMORY_FORWARD_DECLARED 1
+#endif
+
+#endif /* _TEST_SUPPORT_STDLIB_MEMORY */
diff --git a/pstl/test/support/stdlib/numeric b/pstl/test/support/stdlib/numeric
new file mode 100644
index 0000000..8f98bc7
--- /dev/null
+++ b/pstl/test/support/stdlib/numeric
@@ -0,0 +1,26 @@
+// -*- C++ -*-
+//===-- numeric -----------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _TEST_SUPPORT_STDLIB_NUMERIC
+#define _TEST_SUPPORT_STDLIB_NUMERIC
+
+#include_next <numeric>
+
+#include <pstl/internal/pstl_config.h>
+
+#if _PSTL_EXECUTION_POLICIES_DEFINED
+// If <execution> has already been included, pull in implementations
+#    include <pstl/internal/glue_numeric_impl.h>
+#else
+// Otherwise just pull in forward declarations
+#    include <pstl/internal/glue_numeric_defs.h>
+#    define _PSTL_NUMERIC_FORWARD_DECLARED 1
+#endif
+
+#endif /* _TEST_SUPPORT_STDLIB_NUMERIC */
diff --git a/pstl/test/support/utils.h b/pstl/test/support/utils.h
new file mode 100644
index 0000000..ed6d48b
--- /dev/null
+++ b/pstl/test/support/utils.h
@@ -0,0 +1,1318 @@
+// -*- C++ -*-
+//===-- utils.h -----------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// File contains common utilities that tests rely on
+
+// Do not #include <algorithm>, because if we do we will not detect accidental dependencies.
+#include <atomic>
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+#include <iostream>
+#include <iterator>
+#include <memory>
+#include <sstream>
+#include <vector>
+
+#include "pstl_test_config.h"
+
+namespace TestUtils
+{
+
+typedef double float64_t;
+typedef float float32_t;
+
+template <class T, std::size_t N>
+constexpr size_t
+const_size(const T (&)[N]) noexcept
+{
+    return N;
+}
+
+template <typename T>
+class Sequence;
+
+// Handy macros for error reporting
+#define EXPECT_TRUE(condition, message) ::TestUtils::expect(true, condition, __FILE__, __LINE__, message)
+#define EXPECT_FALSE(condition, message) ::TestUtils::expect(false, condition, __FILE__, __LINE__, message)
+
+// Check that expected and actual are equal and have the same type.
+#define EXPECT_EQ(expected, actual, message) ::TestUtils::expect_equal(expected, actual, __FILE__, __LINE__, message)
+
+// Check that sequences started with expected and actual and have had size n are equal and have the same type.
+#define EXPECT_EQ_N(expected, actual, n, message)                                                                      \
+    ::TestUtils::expect_equal(expected, actual, n, __FILE__, __LINE__, message)
+
+// Issue error message from outstr, adding a newline.
+// Real purpose of this routine is to have a place to hang a breakpoint.
+inline void
+issue_error_message(std::stringstream& outstr)
+{
+    outstr << std::endl;
+    std::cerr << outstr.str();
+    std::exit(EXIT_FAILURE);
+}
+
+inline void
+expect(bool expected, bool condition, const char* file, int32_t line, const char* message)
+{
+    if (condition != expected)
+    {
+        std::stringstream outstr;
+        outstr << "error at " << file << ":" << line << " - " << message;
+        issue_error_message(outstr);
+    }
+}
+
+// Do not change signature to const T&.
+// Function must be able to detect const differences between expected and actual.
+template <typename T>
+void
+expect_equal(T& expected, T& actual, const char* file, int32_t line, const char* message)
+{
+    if (!(expected == actual))
+    {
+        std::stringstream outstr;
+        outstr << "error at " << file << ":" << line << " - " << message << ", expected " << expected << " got "
+               << actual;
+        issue_error_message(outstr);
+    }
+}
+
+template <typename T>
+void
+expect_equal(Sequence<T>& expected, Sequence<T>& actual, const char* file, int32_t line, const char* message)
+{
+    size_t n = expected.size();
+    size_t m = actual.size();
+    if (n != m)
+    {
+        std::stringstream outstr;
+        outstr << "error at " << file << ":" << line << " - " << message << ", expected sequence of size " << n
+               << " got sequence of size " << m;
+        issue_error_message(outstr);
+        return;
+    }
+    size_t error_count = 0;
+    for (size_t k = 0; k < n && error_count < 10; ++k)
+    {
+        if (!(expected[k] == actual[k]))
+        {
+            std::stringstream outstr;
+            outstr << "error at " << file << ":" << line << " - " << message << ", at index " << k << " expected "
+                   << expected[k] << " got " << actual[k];
+            issue_error_message(outstr);
+            ++error_count;
+        }
+    }
+}
+
+template <typename Iterator1, typename Iterator2, typename Size>
+void
+expect_equal(Iterator1 expected_first, Iterator2 actual_first, Size n, const char* file, int32_t line,
+             const char* message)
+{
+    size_t error_count = 0;
+    for (Size k = 0; k < n && error_count < 10; ++k, ++expected_first, ++actual_first)
+    {
+        if (!(*expected_first == *actual_first))
+        {
+            std::stringstream outstr;
+            outstr << "error at " << file << ":" << line << " - " << message << ", at index " << k;
+            issue_error_message(outstr);
+            ++error_count;
+        }
+    }
+}
+
+// ForwardIterator is like type Iterator, but restricted to be a forward iterator.
+// Only the forward iterator signatures that are necessary for tests are present.
+// Post-increment in particular is deliberatly omitted since our templates should avoid using it
+// because of efficiency considerations.
+template <typename Iterator, typename IteratorTag>
+class ForwardIterator
+{
+  public:
+    typedef IteratorTag iterator_category;
+    typedef typename std::iterator_traits<Iterator>::value_type value_type;
+    typedef typename std::iterator_traits<Iterator>::difference_type difference_type;
+    typedef typename std::iterator_traits<Iterator>::pointer pointer;
+    typedef typename std::iterator_traits<Iterator>::reference reference;
+
+  protected:
+    Iterator my_iterator;
+    typedef value_type element_type;
+
+  public:
+    ForwardIterator() = default;
+    explicit ForwardIterator(Iterator i) : my_iterator(i) {}
+    reference operator*() const { return *my_iterator; }
+    Iterator operator->() const { return my_iterator; }
+    ForwardIterator
+    operator++()
+    {
+        ++my_iterator;
+        return *this;
+    }
+    ForwardIterator operator++(int32_t)
+    {
+        auto retval = *this;
+        my_iterator++;
+        return retval;
+    }
+    friend bool
+    operator==(const ForwardIterator& i, const ForwardIterator& j)
+    {
+        return i.my_iterator == j.my_iterator;
+    }
+    friend bool
+    operator!=(const ForwardIterator& i, const ForwardIterator& j)
+    {
+        return i.my_iterator != j.my_iterator;
+    }
+
+    Iterator
+    iterator() const
+    {
+        return my_iterator;
+    }
+};
+
+template <typename Iterator, typename IteratorTag>
+class BidirectionalIterator : public ForwardIterator<Iterator, IteratorTag>
+{
+    typedef ForwardIterator<Iterator, IteratorTag> base_type;
+
+  public:
+    BidirectionalIterator() = default;
+    explicit BidirectionalIterator(Iterator i) : base_type(i) {}
+    BidirectionalIterator(const base_type& i) : base_type(i.iterator()) {}
+
+    BidirectionalIterator
+    operator++()
+    {
+        ++base_type::my_iterator;
+        return *this;
+    }
+    BidirectionalIterator
+    operator--()
+    {
+        --base_type::my_iterator;
+        return *this;
+    }
+    BidirectionalIterator operator++(int32_t)
+    {
+        auto retval = *this;
+        base_type::my_iterator++;
+        return retval;
+    }
+    BidirectionalIterator operator--(int32_t)
+    {
+        auto retval = *this;
+        base_type::my_iterator--;
+        return retval;
+    }
+};
+
+template <typename Iterator, typename F>
+void
+fill_data(Iterator first, Iterator last, F f)
+{
+    typedef typename std::iterator_traits<Iterator>::value_type T;
+    for (std::size_t i = 0; first != last; ++first, ++i)
+    {
+        *first = T(f(i));
+    }
+}
+
+struct MemoryChecker {
+    // static counters and state tags
+    static std::atomic<std::int64_t> alive_object_counter; // initialized outside
+    static constexpr std::int64_t alive_state = 0xAAAAAAAAAAAAAAAA;
+    static constexpr std::int32_t dead_state = 0; // only used as a set value to cancel alive_state
+
+    std::int32_t _value; // object value used for algorithms
+    std::int64_t _state; // state tag used for checks
+
+    // ctors, dtors, assign ops
+    explicit MemoryChecker(std::int32_t value = 0) : _value(value) {
+        // check for EXPECT_TRUE(state() != alive_state, ...) has not been done since we cannot guarantee that
+        // raw memory for object being constructed does not have a bit sequence being equal to alive_state
+
+        // set constructed state and increment counter for living object
+        inc_alive_objects();
+        _state = alive_state;
+    }
+    MemoryChecker(MemoryChecker&& other) : _value(other.value()) {
+        // check for EXPECT_TRUE(state() != alive_state, ...) has not been done since
+        // compiler can optimize out the move ctor call that results in false positive failure
+        EXPECT_TRUE(other.state() == alive_state, "wrong effect from MemoryChecker(MemoryChecker&&): attemp to construct an object from non-existing object");
+        // set constructed state and increment counter for living object
+        inc_alive_objects();
+        _state = alive_state;
+    }
+    MemoryChecker(const MemoryChecker& other) : _value(other.value()) {
+        // check for EXPECT_TRUE(state() != alive_state, ...) has not been done since
+        // compiler can optimize out the copy ctor call that results in false positive failure
+        EXPECT_TRUE(other.state() == alive_state, "wrong effect from MemoryChecker(const MemoryChecker&): attemp to construct an object from non-existing object");
+        // set constructed state and increment counter for living object
+        inc_alive_objects();
+        _state = alive_state;
+    }
+    MemoryChecker& operator=(MemoryChecker&& other) {
+        // check if we do not assign over uninitialized memory
+        EXPECT_TRUE(state() == alive_state, "wrong effect from MemoryChecker::operator=(MemoryChecker&& other): attemp to assign to non-existing object");
+        EXPECT_TRUE(other.state() == alive_state, "wrong effect from MemoryChecker::operator=(MemoryChecker&& other): attemp to assign from non-existing object");
+        // just assign new value, counter is the same, state is the same
+        _value = other.value();
+
+        return *this;
+    }
+    MemoryChecker& operator=(const MemoryChecker& other) {
+        // check if we do not assign over uninitialized memory
+        EXPECT_TRUE(state() == alive_state, "wrong effect from MemoryChecker::operator=(const MemoryChecker& other): attemp to assign to non-existing object");
+        EXPECT_TRUE(other.state() == alive_state, "wrong effect from MemoryChecker::operator=(const MemoryChecker& other): attemp to assign from non-existing object");
+        // just assign new value, counter is the same, state is the same
+        _value = other.value();
+
+        return *this;
+    }
+    ~MemoryChecker() {
+        // check if we do not double destruct the object
+        EXPECT_TRUE(state() == alive_state, "wrong effect from ~MemoryChecker(): attemp to destroy non-existing object");
+        // set destructed state and decrement counter for living object
+        static_cast<volatile std::int64_t&>(_state) = dead_state;
+        dec_alive_objects();
+    }
+
+    // getters
+    std::int32_t value() const { return _value; }
+    std::int64_t state() const { return _state; }
+    static std::int32_t alive_objects() { return alive_object_counter.load(); }
+private:
+    // setters
+    void inc_alive_objects() { alive_object_counter.fetch_add(1); }
+    void dec_alive_objects() { alive_object_counter.fetch_sub(1); }
+};
+
+std::atomic<std::int64_t> MemoryChecker::alive_object_counter{0};
+
+std::ostream& operator<<(std::ostream& os, const MemoryChecker& val) { return (os << val.value()); }
+bool operator==(const MemoryChecker& v1, const MemoryChecker& v2) { return v1.value() == v2.value(); }
+bool operator<(const MemoryChecker& v1, const MemoryChecker& v2) { return v1.value() < v2.value(); }
+
+// Sequence<T> is a container of a sequence of T with lots of kinds of iterators.
+// Prefixes on begin/end mean:
+//      c = "const"
+//      f = "forward"
+// No prefix indicates non-const random-access iterator.
+template <typename T>
+class Sequence
+{
+    std::vector<T> m_storage;
+
+  public:
+    typedef typename std::vector<T>::iterator iterator;
+    typedef typename std::vector<T>::const_iterator const_iterator;
+    typedef ForwardIterator<iterator, std::forward_iterator_tag> forward_iterator;
+    typedef ForwardIterator<const_iterator, std::forward_iterator_tag> const_forward_iterator;
+
+    typedef BidirectionalIterator<iterator, std::bidirectional_iterator_tag> bidirectional_iterator;
+    typedef BidirectionalIterator<const_iterator, std::bidirectional_iterator_tag> const_bidirectional_iterator;
+
+    typedef T value_type;
+    explicit Sequence(size_t size) : m_storage(size) {}
+
+    // Construct sequence [f(0), f(1), ... f(size-1)]
+    // f can rely on its invocations being sequential from 0 to size-1.
+    template <typename Func>
+    Sequence(size_t size, Func f)
+    {
+        m_storage.reserve(size);
+        // Use push_back because T might not have a default constructor
+        for (size_t k = 0; k < size; ++k)
+            m_storage.push_back(T(f(k)));
+    }
+    Sequence(const std::initializer_list<T>& data) : m_storage(data) {}
+
+    const_iterator
+    begin() const
+    {
+        return m_storage.begin();
+    }
+    const_iterator
+    end() const
+    {
+        return m_storage.end();
+    }
+    iterator
+    begin()
+    {
+        return m_storage.begin();
+    }
+    iterator
+    end()
+    {
+        return m_storage.end();
+    }
+    const_iterator
+    cbegin() const
+    {
+        return m_storage.cbegin();
+    }
+    const_iterator
+    cend() const
+    {
+        return m_storage.cend();
+    }
+    forward_iterator
+    fbegin()
+    {
+        return forward_iterator(m_storage.begin());
+    }
+    forward_iterator
+    fend()
+    {
+        return forward_iterator(m_storage.end());
+    }
+    const_forward_iterator
+    cfbegin() const
+    {
+        return const_forward_iterator(m_storage.cbegin());
+    }
+    const_forward_iterator
+    cfend() const
+    {
+        return const_forward_iterator(m_storage.cend());
+    }
+    const_forward_iterator
+    fbegin() const
+    {
+        return const_forward_iterator(m_storage.cbegin());
+    }
+    const_forward_iterator
+    fend() const
+    {
+        return const_forward_iterator(m_storage.cend());
+    }
+
+    const_bidirectional_iterator
+    cbibegin() const
+    {
+        return const_bidirectional_iterator(m_storage.cbegin());
+    }
+    const_bidirectional_iterator
+    cbiend() const
+    {
+        return const_bidirectional_iterator(m_storage.cend());
+    }
+
+    bidirectional_iterator
+    bibegin()
+    {
+        return bidirectional_iterator(m_storage.begin());
+    }
+    bidirectional_iterator
+    biend()
+    {
+        return bidirectional_iterator(m_storage.end());
+    }
+
+    std::size_t
+    size() const
+    {
+        return m_storage.size();
+    }
+    const T*
+    data() const
+    {
+        return m_storage.data();
+    }
+    typename std::vector<T>::reference operator[](size_t j) { return m_storage[j]; }
+    const T& operator[](size_t j) const { return m_storage[j]; }
+
+    // Fill with given value
+    void
+    fill(const T& value)
+    {
+        for (size_t i = 0; i < m_storage.size(); i++)
+            m_storage[i] = value;
+    }
+
+    void
+    print() const;
+
+    template <typename Func>
+    void
+    fill(Func f)
+    {
+        fill_data(m_storage.begin(), m_storage.end(), f);
+    }
+};
+
+template <typename T>
+void
+Sequence<T>::print() const
+{
+    std::cout << "size = " << size() << ": { ";
+    std::copy(begin(), end(), std::ostream_iterator<T>(std::cout, " "));
+    std::cout << " } " << std::endl;
+}
+
+// Predicates for algorithms
+template <typename DataType>
+struct is_equal_to
+{
+    is_equal_to(const DataType& expected) : m_expected(expected) {}
+    bool
+    operator()(const DataType& actual) const
+    {
+        return actual == m_expected;
+    }
+
+  private:
+    DataType m_expected;
+};
+
+// Low-quality hash function, returns value between 0 and (1<<bits)-1
+// Warning: low-order bits are quite predictable.
+inline size_t
+HashBits(size_t i, size_t bits)
+{
+    size_t mask = bits >= 8 * sizeof(size_t) ? ~size_t(0) : (size_t(1) << bits) - 1;
+    return (424157 * i ^ 0x24aFa) & mask;
+}
+
+// Stateful unary op
+template <typename T, typename U>
+class Complement
+{
+    int32_t val;
+
+  public:
+    Complement(T v) : val(v) {}
+    U
+    operator()(const T& x) const
+    {
+        return U(val - x);
+    }
+};
+
+// Tag used to prevent accidental use of converting constructor, even if use is explicit.
+struct OddTag
+{
+};
+
+class Sum;
+
+// Type with limited set of operations.  Not default-constructible.
+// Only available operator is "==".
+// Typically used as value type in tests.
+class Number
+{
+    int32_t value;
+    friend class Add;
+    friend class Sum;
+    friend class IsMultiple;
+    friend class Congruent;
+    friend Sum
+    operator+(const Sum& x, const Sum& y);
+
+  public:
+    Number(int32_t val, OddTag) : value(val) {}
+    friend bool
+    operator==(const Number& x, const Number& y)
+    {
+        return x.value == y.value;
+    }
+    friend std::ostream&
+    operator<<(std::ostream& o, const Number& d)
+    {
+        return o << d.value;
+    }
+};
+
+// Stateful predicate for Number.  Not default-constructible.
+class IsMultiple
+{
+    long modulus;
+
+  public:
+    // True if x is multiple of modulus
+    bool
+    operator()(Number x) const
+    {
+        return x.value % modulus == 0;
+    }
+    IsMultiple(long modulus_, OddTag) : modulus(modulus_) {}
+};
+
+// Stateful equivalence-class predicate for Number.  Not default-constructible.
+class Congruent
+{
+    long modulus;
+
+  public:
+    // True if x and y have same remainder for the given modulus.
+    // Note: this is not quite the same as "equivalent modulo modulus" when x and y have different
+    // sign, but nonetheless AreCongruent is still an equivalence relationship, which is all
+    // we need for testing.
+    bool
+    operator()(Number x, Number y) const
+    {
+        return x.value % modulus == y.value % modulus;
+    }
+    Congruent(long modulus_, OddTag) : modulus(modulus_) {}
+};
+
+// Stateful reduction operation for Number
+class Add
+{
+    long bias;
+
+  public:
+    explicit Add(OddTag) : bias(1) {}
+    Number
+    operator()(Number x, const Number& y)
+    {
+        return Number(x.value + y.value + (bias - 1), OddTag());
+    }
+};
+
+// Class similar to Number, but has default constructor and +.
+class Sum : public Number
+{
+  public:
+    Sum() : Number(0, OddTag()) {}
+    Sum(long x, OddTag) : Number(x, OddTag()) {}
+    friend Sum
+    operator+(const Sum& x, const Sum& y)
+    {
+        return Sum(x.value + y.value, OddTag());
+    }
+};
+
+// Type with limited set of operations, which includes an associative but not commutative operation.
+// Not default-constructible.
+// Typically used as value type in tests involving "GENERALIZED_NONCOMMUTATIVE_SUM".
+class MonoidElement
+{
+    size_t a, b;
+
+  public:
+    MonoidElement(size_t a_, size_t b_, OddTag) : a(a_), b(b_) {}
+    friend bool
+    operator==(const MonoidElement& x, const MonoidElement& y)
+    {
+        return x.a == y.a && x.b == y.b;
+    }
+    friend std::ostream&
+    operator<<(std::ostream& o, const MonoidElement& x)
+    {
+        return o << "[" << x.a << ".." << x.b << ")";
+    }
+    friend class AssocOp;
+};
+
+// Stateful associative op for MonoidElement
+// It's not really a monoid since the operation is not allowed for any two elements.
+// But it's good enough for testing.
+class AssocOp
+{
+    unsigned c;
+
+  public:
+    explicit AssocOp(OddTag) : c(5) {}
+    MonoidElement
+    operator()(const MonoidElement& x, const MonoidElement& y)
+    {
+        unsigned d = 5;
+        EXPECT_EQ(d, c, "state lost");
+        EXPECT_EQ(x.b, y.a, "commuted?");
+
+        return MonoidElement(x.a, y.b, OddTag());
+    }
+};
+
+// Multiplication of matrix is an associative but not commutative operation
+// Typically used as value type in tests involving "GENERALIZED_NONCOMMUTATIVE_SUM".
+template <typename T>
+struct Matrix2x2
+{
+    T a[2][2];
+    Matrix2x2() : a{{1, 0}, {0, 1}} {}
+    Matrix2x2(T x, T y) : a{{0, x}, {x, y}} {}
+#if !defined(_PSTL_ICL_19_VC14_VC141_TEST_SCAN_RELEASE_BROKEN)
+    Matrix2x2(const Matrix2x2& m) : a{{m.a[0][0], m.a[0][1]}, {m.a[1][0], m.a[1][1]}} {}
+    Matrix2x2&
+    operator=(const Matrix2x2& m)
+    {
+        a[0][0] = m.a[0][0], a[0][1] = m.a[0][1], a[1][0] = m.a[1][0], a[1][1] = m.a[1][1];
+        return *this;
+    }
+#endif
+};
+
+template <typename T>
+bool
+operator==(const Matrix2x2<T>& left, const Matrix2x2<T>& right)
+{
+    return left.a[0][0] == right.a[0][0] && left.a[0][1] == right.a[0][1] && left.a[1][0] == right.a[1][0] &&
+           left.a[1][1] == right.a[1][1];
+}
+
+template <typename T>
+Matrix2x2<T>
+multiply_matrix(const Matrix2x2<T>& left, const Matrix2x2<T>& right)
+{
+    Matrix2x2<T> result;
+    for (int32_t i = 0; i < 2; ++i)
+    {
+        for (int32_t j = 0; j < 2; ++j)
+        {
+            result.a[i][j] = left.a[i][0] * right.a[0][j] + left.a[i][1] * right.a[1][j];
+        }
+    }
+    return result;
+}
+
+//============================================================================
+// Adapters for creating different types of iterators.
+//
+// In this block we implemented some adapters for creating differnet types of iterators.
+// It's needed for extending the unit testing of Parallel STL algorithms.
+// We have adapters for iterators with different tags (forward_iterator_tag, bidirectional_iterator_tag), reverse iterators.
+// The input iterator should be const or non-const, non-reverse random access iterator.
+// Iterator creates in "MakeIterator":
+// firstly, iterator is "packed" by "IteratorTypeAdapter" (creating forward or bidirectional iterator)
+// then iterator is "packed" by "ReverseAdapter" (if it's possible)
+// So, from input iterator we may create, for example, reverse bidirectional iterator.
+// "Main" functor for testing iterators is named "invoke_on_all_iterator_types".
+
+// Base adapter
+template <typename Iterator>
+struct BaseAdapter
+{
+    typedef Iterator iterator_type;
+    iterator_type
+    operator()(Iterator it)
+    {
+        return it;
+    }
+};
+
+// Check if the iterator is reverse iterator
+// Note: it works only for iterators that created by std::reverse_iterator
+template <typename NotReverseIterator>
+struct isReverse : std::false_type
+{
+};
+
+template <typename Iterator>
+struct isReverse<std::reverse_iterator<Iterator>> : std::true_type
+{
+};
+
+// Reverse adapter
+template <typename Iterator, typename IsReverse>
+struct ReverseAdapter
+{
+    typedef std::reverse_iterator<Iterator> iterator_type;
+    iterator_type
+    operator()(Iterator it)
+    {
+#if defined(_PSTL_CPP14_MAKE_REVERSE_ITERATOR_PRESENT)
+        return std::make_reverse_iterator(it);
+#else
+        return iterator_type(it);
+#endif
+    }
+};
+
+// Non-reverse adapter
+template <typename Iterator>
+struct ReverseAdapter<Iterator, std::false_type> : BaseAdapter<Iterator>
+{
+};
+
+// Iterator adapter by type (by default std::random_access_iterator_tag)
+template <typename Iterator, typename IteratorTag>
+struct IteratorTypeAdapter : BaseAdapter<Iterator>
+{
+};
+
+// Iterator adapter for forward iterator
+template <typename Iterator>
+struct IteratorTypeAdapter<Iterator, std::forward_iterator_tag>
+{
+    typedef ForwardIterator<Iterator, std::forward_iterator_tag> iterator_type;
+    iterator_type
+    operator()(Iterator it)
+    {
+        return iterator_type(it);
+    }
+};
+
+// Iterator adapter for bidirectional iterator
+template <typename Iterator>
+struct IteratorTypeAdapter<Iterator, std::bidirectional_iterator_tag>
+{
+    typedef BidirectionalIterator<Iterator, std::bidirectional_iterator_tag> iterator_type;
+    iterator_type
+    operator()(Iterator it)
+    {
+        return iterator_type(it);
+    }
+};
+
+//For creating iterator with new type
+template <typename InputIterator, typename IteratorTag, typename IsReverse>
+struct MakeIterator
+{
+    typedef IteratorTypeAdapter<InputIterator, IteratorTag> IterByType;
+    typedef ReverseAdapter<typename IterByType::iterator_type, IsReverse> ReverseIter;
+
+    typename ReverseIter::iterator_type
+    operator()(InputIterator it)
+    {
+        return ReverseIter()(IterByType()(it));
+    }
+};
+
+// Useful constant variables
+constexpr std::size_t GuardSize = 5;
+constexpr std::ptrdiff_t sizeLimit = 1000;
+
+template <typename Iter, typename Void = void> // local iterator_traits for non-iterators
+struct iterator_traits_
+{
+};
+
+template <typename Iter> // For iterators
+struct iterator_traits_<Iter,
+                        typename std::enable_if<!std::is_void<typename Iter::iterator_category>::value, void>::type>
+{
+    typedef typename Iter::iterator_category iterator_category;
+};
+
+template <typename T> // For pointers
+struct iterator_traits_<T*>
+{
+    typedef std::random_access_iterator_tag iterator_category;
+};
+
+// is iterator Iter has tag Tag
+template <typename Iter, typename Tag>
+using is_same_iterator_category = std::is_same<typename iterator_traits_<Iter>::iterator_category, Tag>;
+
+// if we run with reverse or const iterators we shouldn't test the large range
+template <typename IsReverse, typename IsConst>
+struct invoke_if_
+{
+    template <typename Op, typename... Rest>
+    void
+    operator()(bool is_allow, Op op, Rest&&... rest)
+    {
+        if (is_allow)
+            op(std::forward<Rest>(rest)...);
+    }
+};
+template <>
+struct invoke_if_<std::false_type, std::false_type>
+{
+    template <typename Op, typename... Rest>
+    void
+    operator()(bool, Op op, Rest&&... rest)
+    {
+        op(std::forward<Rest>(rest)...);
+    }
+};
+
+// Base non_const_wrapper struct. It is used to distinguish non_const testcases
+// from a regular one. For non_const testcases only compilation is checked.
+struct non_const_wrapper
+{
+};
+
+// Generic wrapper to specify iterator type to execute callable Op on.
+// The condition can be either positive(Op is executed only with IteratorTag)
+// or negative(Op is executed with every type of iterators except IteratorTag)
+template <typename Op, typename IteratorTag, bool IsPositiveCondition = true>
+struct non_const_wrapper_tagged : non_const_wrapper
+{
+    template <typename Policy, typename Iterator>
+    typename std::enable_if<IsPositiveCondition == is_same_iterator_category<Iterator, IteratorTag>::value, void>::type
+    operator()(Policy&& exec, Iterator iter)
+    {
+        Op()(exec, iter);
+    }
+
+    template <typename Policy, typename InputIterator, typename OutputIterator>
+    typename std::enable_if<IsPositiveCondition == is_same_iterator_category<OutputIterator, IteratorTag>::value,
+                            void>::type
+    operator()(Policy&& exec, InputIterator input_iter, OutputIterator out_iter)
+    {
+        Op()(exec, input_iter, out_iter);
+    }
+
+    template <typename Policy, typename Iterator>
+    typename std::enable_if<IsPositiveCondition != is_same_iterator_category<Iterator, IteratorTag>::value, void>::type
+    operator()(Policy&&, Iterator)
+    {
+    }
+
+    template <typename Policy, typename InputIterator, typename OutputIterator>
+    typename std::enable_if<IsPositiveCondition != is_same_iterator_category<OutputIterator, IteratorTag>::value,
+                            void>::type
+    operator()(Policy&&, InputIterator, OutputIterator)
+    {
+    }
+};
+
+// These run_for_* structures specify with which types of iterators callable object Op
+// should be executed.
+template <typename Op>
+struct run_for_rnd : non_const_wrapper_tagged<Op, std::random_access_iterator_tag>
+{
+};
+
+template <typename Op>
+struct run_for_rnd_bi : non_const_wrapper_tagged<Op, std::forward_iterator_tag, false>
+{
+};
+
+template <typename Op>
+struct run_for_rnd_fw : non_const_wrapper_tagged<Op, std::bidirectional_iterator_tag, false>
+{
+};
+
+// Invoker for different types of iterators.
+template <typename IteratorTag, typename IsReverse>
+struct iterator_invoker
+{
+    template <typename Iterator>
+    using make_iterator = MakeIterator<Iterator, IteratorTag, IsReverse>;
+    template <typename Iterator>
+    using IsConst = typename std::is_const<
+        typename std::remove_pointer<typename std::iterator_traits<Iterator>::pointer>::type>::type;
+    template <typename Iterator>
+    using invoke_if = invoke_if_<IsReverse, IsConst<Iterator>>;
+
+    // A single iterator version which is used for non_const testcases
+    template <typename Policy, typename Op, typename Iterator>
+    typename std::enable_if<is_same_iterator_category<Iterator, std::random_access_iterator_tag>::value &&
+                                std::is_base_of<non_const_wrapper, Op>::value,
+                            void>::type
+    operator()(Policy&& exec, Op op, Iterator iter)
+    {
+        op(std::forward<Policy>(exec), make_iterator<Iterator>()(iter));
+    }
+
+    // A version with 2 iterators which is used for non_const testcases
+    template <typename Policy, typename Op, typename InputIterator, typename OutputIterator>
+    typename std::enable_if<is_same_iterator_category<OutputIterator, std::random_access_iterator_tag>::value &&
+                                std::is_base_of<non_const_wrapper, Op>::value,
+                            void>::type
+    operator()(Policy&& exec, Op op, InputIterator input_iter, OutputIterator out_iter)
+    {
+        op(std::forward<Policy>(exec), make_iterator<InputIterator>()(input_iter),
+           make_iterator<OutputIterator>()(out_iter));
+    }
+
+    template <typename Policy, typename Op, typename Iterator, typename Size, typename... Rest>
+    typename std::enable_if<is_same_iterator_category<Iterator, std::random_access_iterator_tag>::value, void>::type
+    operator()(Policy&& exec, Op op, Iterator begin, Size n, Rest&&... rest)
+    {
+        invoke_if<Iterator>()(n <= sizeLimit, op, exec, make_iterator<Iterator>()(begin), n,
+                              std::forward<Rest>(rest)...);
+    }
+
+    template <typename Policy, typename Op, typename Iterator, typename... Rest>
+    typename std::enable_if<is_same_iterator_category<Iterator, std::random_access_iterator_tag>::value &&
+                                !std::is_base_of<non_const_wrapper, Op>::value,
+                            void>::type
+    operator()(Policy&& exec, Op op, Iterator inputBegin, Iterator inputEnd, Rest&&... rest)
+    {
+        invoke_if<Iterator>()(std::distance(inputBegin, inputEnd) <= sizeLimit, op, exec,
+                              make_iterator<Iterator>()(inputBegin), make_iterator<Iterator>()(inputEnd),
+                              std::forward<Rest>(rest)...);
+    }
+
+    template <typename Policy, typename Op, typename InputIterator, typename OutputIterator, typename... Rest>
+    typename std::enable_if<is_same_iterator_category<OutputIterator, std::random_access_iterator_tag>::value,
+                            void>::type
+    operator()(Policy&& exec, Op op, InputIterator inputBegin, InputIterator inputEnd, OutputIterator outputBegin,
+               Rest&&... rest)
+    {
+        invoke_if<InputIterator>()(std::distance(inputBegin, inputEnd) <= sizeLimit, op, exec,
+                                   make_iterator<InputIterator>()(inputBegin), make_iterator<InputIterator>()(inputEnd),
+                                   make_iterator<OutputIterator>()(outputBegin), std::forward<Rest>(rest)...);
+    }
+
+    template <typename Policy, typename Op, typename InputIterator, typename OutputIterator, typename... Rest>
+    typename std::enable_if<is_same_iterator_category<OutputIterator, std::random_access_iterator_tag>::value,
+                            void>::type
+    operator()(Policy&& exec, Op op, InputIterator inputBegin, InputIterator inputEnd, OutputIterator outputBegin,
+               OutputIterator outputEnd, Rest&&... rest)
+    {
+        invoke_if<InputIterator>()(std::distance(inputBegin, inputEnd) <= sizeLimit, op, exec,
+                                   make_iterator<InputIterator>()(inputBegin), make_iterator<InputIterator>()(inputEnd),
+                                   make_iterator<OutputIterator>()(outputBegin),
+                                   make_iterator<OutputIterator>()(outputEnd), std::forward<Rest>(rest)...);
+    }
+
+    template <typename Policy, typename Op, typename InputIterator1, typename InputIterator2, typename OutputIterator,
+              typename... Rest>
+    typename std::enable_if<is_same_iterator_category<OutputIterator, std::random_access_iterator_tag>::value,
+                            void>::type
+    operator()(Policy&& exec, Op op, InputIterator1 inputBegin1, InputIterator1 inputEnd1, InputIterator2 inputBegin2,
+               InputIterator2 inputEnd2, OutputIterator outputBegin, OutputIterator outputEnd, Rest&&... rest)
+    {
+        invoke_if<InputIterator1>()(
+            std::distance(inputBegin1, inputEnd1) <= sizeLimit, op, exec, make_iterator<InputIterator1>()(inputBegin1),
+            make_iterator<InputIterator1>()(inputEnd1), make_iterator<InputIterator2>()(inputBegin2),
+            make_iterator<InputIterator2>()(inputEnd2), make_iterator<OutputIterator>()(outputBegin),
+            make_iterator<OutputIterator>()(outputEnd), std::forward<Rest>(rest)...);
+    }
+};
+
+// Invoker for reverse iterators only
+// Note: if we run with reverse iterators we shouldn't test the large range
+template <typename IteratorTag>
+struct iterator_invoker<IteratorTag, /* IsReverse = */ std::true_type>
+{
+
+    template <typename Iterator>
+    using make_iterator = MakeIterator<Iterator, IteratorTag, std::true_type>;
+
+    // A single iterator version which is used for non_const testcases
+    template <typename Policy, typename Op, typename Iterator>
+    typename std::enable_if<is_same_iterator_category<Iterator, std::random_access_iterator_tag>::value &&
+                                std::is_base_of<non_const_wrapper, Op>::value,
+                            void>::type
+    operator()(Policy&& exec, Op op, Iterator iter)
+    {
+        op(std::forward<Policy>(exec), make_iterator<Iterator>()(iter));
+    }
+
+    // A version with 2 iterators which is used for non_const testcases
+    template <typename Policy, typename Op, typename InputIterator, typename OutputIterator>
+    typename std::enable_if<is_same_iterator_category<OutputIterator, std::random_access_iterator_tag>::value &&
+                                std::is_base_of<non_const_wrapper, Op>::value,
+                            void>::type
+    operator()(Policy&& exec, Op op, InputIterator input_iter, OutputIterator out_iter)
+    {
+        op(std::forward<Policy>(exec), make_iterator<InputIterator>()(input_iter),
+           make_iterator<OutputIterator>()(out_iter));
+    }
+
+    template <typename Policy, typename Op, typename Iterator, typename Size, typename... Rest>
+    typename std::enable_if<is_same_iterator_category<Iterator, std::random_access_iterator_tag>::value, void>::type
+    operator()(Policy&& exec, Op op, Iterator begin, Size n, Rest&&... rest)
+    {
+        if (n <= sizeLimit)
+            op(exec, make_iterator<Iterator>()(begin + n), n, std::forward<Rest>(rest)...);
+    }
+
+    template <typename Policy, typename Op, typename Iterator, typename... Rest>
+    typename std::enable_if<is_same_iterator_category<Iterator, std::random_access_iterator_tag>::value &&
+                                !std::is_base_of<non_const_wrapper, Op>::value,
+                            void>::type
+    operator()(Policy&& exec, Op op, Iterator inputBegin, Iterator inputEnd, Rest&&... rest)
+    {
+        if (std::distance(inputBegin, inputEnd) <= sizeLimit)
+            op(exec, make_iterator<Iterator>()(inputEnd), make_iterator<Iterator>()(inputBegin),
+               std::forward<Rest>(rest)...);
+    }
+
+    template <typename Policy, typename Op, typename InputIterator, typename OutputIterator, typename... Rest>
+    typename std::enable_if<is_same_iterator_category<OutputIterator, std::random_access_iterator_tag>::value,
+                            void>::type
+    operator()(Policy&& exec, Op op, InputIterator inputBegin, InputIterator inputEnd, OutputIterator outputBegin,
+               Rest&&... rest)
+    {
+        if (std::distance(inputBegin, inputEnd) <= sizeLimit)
+            op(exec, make_iterator<InputIterator>()(inputEnd), make_iterator<InputIterator>()(inputBegin),
+               make_iterator<OutputIterator>()(outputBegin + (inputEnd - inputBegin)), std::forward<Rest>(rest)...);
+    }
+
+    template <typename Policy, typename Op, typename InputIterator, typename OutputIterator, typename... Rest>
+    typename std::enable_if<is_same_iterator_category<OutputIterator, std::random_access_iterator_tag>::value,
+                            void>::type
+    operator()(Policy&& exec, Op op, InputIterator inputBegin, InputIterator inputEnd, OutputIterator outputBegin,
+               OutputIterator outputEnd, Rest&&... rest)
+    {
+        if (std::distance(inputBegin, inputEnd) <= sizeLimit)
+            op(exec, make_iterator<InputIterator>()(inputEnd), make_iterator<InputIterator>()(inputBegin),
+               make_iterator<OutputIterator>()(outputEnd), make_iterator<OutputIterator>()(outputBegin),
+               std::forward<Rest>(rest)...);
+    }
+
+    template <typename Policy, typename Op, typename InputIterator1, typename InputIterator2, typename OutputIterator,
+              typename... Rest>
+    typename std::enable_if<is_same_iterator_category<OutputIterator, std::random_access_iterator_tag>::value,
+                            void>::type
+    operator()(Policy&& exec, Op op, InputIterator1 inputBegin1, InputIterator1 inputEnd1, InputIterator2 inputBegin2,
+               InputIterator2 inputEnd2, OutputIterator outputBegin, OutputIterator outputEnd, Rest&&... rest)
+    {
+        if (std::distance(inputBegin1, inputEnd1) <= sizeLimit)
+            op(exec, make_iterator<InputIterator1>()(inputEnd1), make_iterator<InputIterator1>()(inputBegin1),
+               make_iterator<InputIterator2>()(inputEnd2), make_iterator<InputIterator2>()(inputBegin2),
+               make_iterator<OutputIterator>()(outputEnd), make_iterator<OutputIterator>()(outputBegin),
+               std::forward<Rest>(rest)...);
+    }
+};
+
+// We can't create reverse iterator from forward iterator
+template <>
+struct iterator_invoker<std::forward_iterator_tag, /*isReverse=*/std::true_type>
+{
+    template <typename... Rest>
+    void
+    operator()(Rest&&...)
+    {
+    }
+};
+
+template <typename IsReverse>
+struct reverse_invoker
+{
+    template <typename... Rest>
+    void
+    operator()(Rest&&... rest)
+    {
+        // Random-access iterator
+        iterator_invoker<std::random_access_iterator_tag, IsReverse>()(std::forward<Rest>(rest)...);
+
+        // Forward iterator
+        iterator_invoker<std::forward_iterator_tag, IsReverse>()(std::forward<Rest>(rest)...);
+
+        // Bidirectional iterator
+        iterator_invoker<std::bidirectional_iterator_tag, IsReverse>()(std::forward<Rest>(rest)...);
+    }
+};
+
+struct invoke_on_all_iterator_types
+{
+    template <typename... Rest>
+    void
+    operator()(Rest&&... rest)
+    {
+        reverse_invoker</* IsReverse = */ std::false_type>()(std::forward<Rest>(rest)...);
+        reverse_invoker</* IsReverse = */ std::true_type>()(std::forward<Rest>(rest)...);
+    }
+};
+//============================================================================
+
+// Invoke op(policy,rest...) for each possible policy.
+template <typename Op, typename... T>
+void
+invoke_on_all_policies(Op op, T&&... rest)
+{
+    using namespace __pstl::execution;
+
+    // Try static execution policies
+    invoke_on_all_iterator_types()(seq, op, std::forward<T>(rest)...);
+    invoke_on_all_iterator_types()(unseq, op, std::forward<T>(rest)...);
+    invoke_on_all_iterator_types()(par, op, std::forward<T>(rest)...);
+    invoke_on_all_iterator_types()(par_unseq, op, std::forward<T>(rest)...);
+}
+
+template <typename F>
+struct NonConstAdapter
+{
+    F my_f;
+    NonConstAdapter(const F& f) : my_f(f) {}
+
+    template <typename... Types>
+    auto
+    operator()(Types&&... args) -> decltype(std::declval<F>().
+                                            operator()(std::forward<Types>(args)...))
+    {
+        return my_f(std::forward<Types>(args)...);
+    }
+};
+
+template <typename F>
+NonConstAdapter<F>
+non_const(const F& f)
+{
+    return NonConstAdapter<F>(f);
+}
+
+// Wrapper for types. It's need for counting of constructing and destructing objects
+template <typename T>
+class Wrapper
+{
+  public:
+    Wrapper()
+    {
+        my_field = std::shared_ptr<T>(new T());
+        ++my_count;
+    }
+    Wrapper(const T& input)
+    {
+        my_field = std::shared_ptr<T>(new T(input));
+        ++my_count;
+    }
+    Wrapper(const Wrapper& input)
+    {
+        my_field = input.my_field;
+        ++my_count;
+    }
+    Wrapper(Wrapper&& input)
+    {
+        my_field = input.my_field;
+        input.my_field = nullptr;
+        ++move_count;
+    }
+    Wrapper&
+    operator=(const Wrapper& input)
+    {
+        my_field = input.my_field;
+        return *this;
+    }
+    Wrapper&
+    operator=(Wrapper&& input)
+    {
+        my_field = input.my_field;
+        input.my_field = nullptr;
+        ++move_count;
+        return *this;
+    }
+    bool
+    operator==(const Wrapper& input) const
+    {
+        return my_field == input.my_field;
+    }
+    bool
+    operator<(const Wrapper& input) const
+    {
+        return *my_field < *input.my_field;
+    }
+    bool
+    operator>(const Wrapper& input) const
+    {
+        return *my_field > *input.my_field;
+    }
+    friend std::ostream&
+    operator<<(std::ostream& stream, const Wrapper& input)
+    {
+        return stream << *(input.my_field);
+    }
+    ~Wrapper()
+    {
+        --my_count;
+        if (move_count > 0)
+        {
+            --move_count;
+        }
+    }
+    T*
+    get_my_field() const
+    {
+        return my_field.get();
+    };
+    static size_t
+    Count()
+    {
+        return my_count;
+    }
+    static size_t
+    MoveCount()
+    {
+        return move_count;
+    }
+    static void
+    SetCount(const size_t& n)
+    {
+        my_count = n;
+    }
+    static void
+    SetMoveCount(const size_t& n)
+    {
+        move_count = n;
+    }
+
+  private:
+    static std::atomic<size_t> my_count;
+    static std::atomic<size_t> move_count;
+    std::shared_ptr<T> my_field;
+};
+
+template <typename T>
+std::atomic<size_t> Wrapper<T>::my_count = {0};
+
+template <typename T>
+std::atomic<size_t> Wrapper<T>::move_count = {0};
+
+template <typename InputIterator, typename T, typename BinaryOperation, typename UnaryOperation>
+T
+transform_reduce_serial(InputIterator first, InputIterator last, T init, BinaryOperation binary_op,
+                        UnaryOperation unary_op) noexcept
+{
+    for (; first != last; ++first)
+    {
+        init = binary_op(init, unary_op(*first));
+    }
+    return init;
+}
+
+static const char*
+done()
+{
+#if defined(_PSTL_TEST_SUCCESSFUL_KEYWORD)
+    return "done";
+#else
+    return "passed";
+#endif
+}
+
+// test_algo_basic_* functions are used to execute
+// f on a very basic sequence of elements of type T.
+
+// Should be used with unary predicate
+template <typename T, typename F>
+static void
+test_algo_basic_single(F&& f)
+{
+    size_t N = 10;
+    Sequence<T> in(N, [](size_t v) -> T { return T(v); });
+
+    invoke_on_all_policies(f, in.begin());
+}
+
+// Should be used with binary predicate
+template <typename T, typename F>
+static void
+test_algo_basic_double(F&& f)
+{
+    size_t N = 10;
+    Sequence<T> in(N, [](size_t v) -> T { return T(v); });
+    Sequence<T> out(N, [](size_t v) -> T { return T(v); });
+
+    invoke_on_all_policies(f, in.begin(), out.begin());
+}
+
+template <typename Policy, typename F>
+static void
+invoke_if(Policy&&, F f)
+{
+#if defined(_PSTL_ICC_16_VC14_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN) || defined(_PSTL_ICC_17_VC141_TEST_SIMD_LAMBDA_DEBUG_32_BROKEN)
+    using decay_policy = typename std::decay<Policy>::type;
+    using allow_unsequenced =
+        std::integral_constant<bool, (std::is_same<decay_policy, std::execution::unsequenced_policy>::value ||
+                                      std::is_same<decay_policy, std::execution::parallel_unsequenced_policy>::value)>;
+    __pstl::__internal::__invoke_if_not(allow_unsequenced{}, f);
+#else
+    f();
+#endif
+}
+
+} /* namespace TestUtils */